JPH0512646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a flow rate conversion device used for measuring the flow rate of a gas such as air.

“Prior Art” The applicant has filed “Japanese Patent Application No. 61-6958 and Japanese Patent Application No. 62-
No. 91548, we proposed a flow rate conversion device using a cantilever-shaped pressure receiving plate. Patent Application No. 62-91548 has a structure in which the flow rate of fluid is measured by a cantilever-shaped pressure receiving plate, a bypass path is provided in the fluid flow path, and a cantilever-shaped valve is provided in this bypass path. It has a variable orifice structure to control the amount of fluid flowing through the bypass path according to the fluid flow rate, and has a structure that can widen the measurement range from low flow area to large flow area. This feature is characterized by a structure that allows the process to be performed simply by changing the .

``Problems to be Solved by the Invention'' The previously proposed flow rate converter has a structure in which a cantilever valve is provided in the bypass path, so this valve may vibrate depending on the flow of fluid. The disadvantage is that the vibrations cause the fluid to be measured to vibrate, and these vibrations are transmitted to the cantilever-shaped pressure receiving plate for measurement, making it impossible to perform stable measurements.

An object of the present invention is to provide a flow rate conversion device that can eliminate valve vibration in a bypass path and perform stable measurements in any flow rate range.

"Means for Solving the Problem" In the present invention, a measurement hole and a bypass hole are provided in the main body side by side so as to block the flow path through which the fluid to be measured flows, and the fluid passes through this hole on the downstream side of the measurement hole. A cantilever-shaped pressure receiving plate is provided, which is arranged so that the fluid is applied to the plate surface in a direction substantially perpendicular to the plate surface, and is mounted close to and opposite the bypass hole downstream of the bypass hole, and downstream of the measurement hole, It has a laminar flow plate having a through hole made of a plurality of thin tubes that laminarizes the flow of the fluid that has passed through the bypass hole, and a hole through which the fluid that has passed through the measurement hole passes, and this laminar flow plate and the main body A means is provided for dividing the space into a space including the pressure receiving plate, the measurement hole, and the hole in the laminar flow plate, and a space including the bypass hole and the through hole in the laminar flow plate.

According to the configuration of the present invention, the fluid passing through the holes constituting the bypass path flows in a laminar flow through a large number of thin tubes. Since this laminar flow is maintained over a wide range of flow rates from small to large, no vibration occurs in the fluid flow.

Therefore, it is possible to obtain a flow rate conversion device that can stably perform measurements over a wide range from small flow rates to large flow rates without causing the pressure receiving plate to vibrate.

"Embodiment" An embodiment of the present invention is shown in FIGS. 1 to 4. In Fig. 1, 1 is an inlet for the fluid to be measured;
indicates the outlet of the fluid to be measured, and the fluid to be measured (gas) flows in the direction of the arrow x.

3 and 4 are piping connectors, 5 is the flow rate converter main body,
6 indicates a laminar flow plate.

As shown in FIG. 2, the flow rate converter main body 5 has a wall 7 in the center, and a pair of crescent-shaped through holes 8A and 8B forming a bypass path are formed on both sides of the wall 7, and penetrate through the wall 7. A measurement through hole 9 is formed.

The measurement through-hole 9 has a slit shape, and this through-hole 9
A cantilever pressure receiving plate 11 is provided on the downstream side. This cantilever pressure receiving plate 11 is formed of a spring material made of a magnetic material, and the amount of deviation thereof is detected by a detection coil 12. A compensation coil 13 is arranged on the other free end side of the pressure receiving plate 11 so as to perform zero balance compensation. Also, 14 is the pressure receiving plate 1
1 shows a stopper plate that protects 1.

The characteristic structure of this invention is the laminar flow plate 6. As shown in FIG. 3, the laminar flow plate 6 is entirely formed into a flat plate shape, and hexagonal through holes 15A and 15B are formed in the flat laminar flow plate 6 to communicate with the bypass holes 8A and 8B. In addition, a hole 16 is provided on the downstream side of the measurement through-hole 9 provided in the flow rate converter main body 5.
form.

A large number of thin tubes 18 are attached to the through holes 15A and 15B constituting the bypass passage in order to make the flow of fluid laminar. The diameter of the thin tube 18 is, for example, about 0.5 mm. As the fluid flows through this thin tube 18, the fluid flow becomes laminar.

The case is shown in which the through holes 15A and 15B each have a hexagonal shape. By forming the hexagonal shape in this way, small diameter tubes can be stably accommodated. In other words, when a large number of tubes are bundled together, the outer circumference of the bundled tubes naturally becomes hexagonal. For this purpose hole 15
A and 15B are selected to be hexagonal.

"Effects of the Invention" As explained above, according to the present invention, a large number of thin tubes 18 are provided in the bypass path, and all the bypass fluid passes through the thin tubes 18. As the fluid flows through the thin tube 18, the flow of the fluid becomes laminar, the generation of vortices, etc. is suppressed, and the fluid does not vibrate.

Therefore, the pressure receiving plate 11 does not vibrate, and the flow rate can be stably converted into an electrical signal.

However, according to this invention, the laminar flow plate can be made separately from the main body, so assembly is easy.
Furthermore, since the laminar flow operation of the laminar flow plate operates over a wide range from a low flow rate region to a high flow rate range, it is possible to provide a flow rate converter that can measure flow rates over a wide range.

[Brief explanation of the drawing]

Fig. 1 is a sectional view for explaining one embodiment of the present invention, Fig. 2 is a perspective view for explaining the structure of the flow converter main body used in this invention, and Fig. 3 is a cross-sectional view for explaining an embodiment of the present invention. FIG. 4 is a perspective view for explaining the structure of the laminar flow plate, and FIG. 4 is an enlarged sectional view for explaining the structure of the main part of the flow converter main body. 1: Inlet of measured fluid, 2: Outlet, 5: Flow rate converter main body, 6: Laminar flow plate, 7: Wall, 8A,
8B: bypass hole, 9: measurement hole, 11: cantilever pressure plate, 12: detection coil, 18: thin tube.

Claims (1)

[Scope of Claims] 1. A main body provided so as to block a flow path through which a fluid to be measured flows, and in which a measurement hole and a bypass hole are formed side by side; B. A main body provided on the downstream side of the measurement hole, A cantilever-shaped pressure receiving plate arranged so that the fluid passing through the measurement hole hits the plate surface in a direction substantially perpendicular to the plate surface; C a displacement detector for measuring the amount of displacement of this pressure receiving plate; D a displacement detector for measuring the displacement of the above-mentioned bypass hole. A through-hole consisting of a plurality of thin tubes that are installed downstream of the measurement hole and laminarize the flow of the fluid that has passed through the bypass hole; A laminar flow plate having holes through which the passed fluid passes; E a space between the laminar flow plate and the main body; and a space including the pressure receiving plate, the measurement hole, and the hole of the laminar flow plate; A flow rate conversion device comprising: means for dividing a space into a space including a hole and a through hole of the laminar flow plate;