JPH04301518A - Flow rate converting apparatus - Google Patents

Abstract

PURPOSE:To obtain a flow rate converting apparatus with various kinds of the measuring range by forming holes in a pressure receiving surface of a pressure receiving plate and selecting the diameter or the number of the holes, or selecting the spring constant of the pressure receiving plate, thereby to regulate the measuring range of the flow rate. CONSTITUTION:Holes 11A are formed in a pressure receiving surface of a pressure receiving plate 11. The diameter or the number of the holes 11A is suitably selected. Accordingly, the resistance value to the flow pressure of the pressure receiving plate 11 can be changed. In other words, when the holes 11A are not, formed, the resistance value is maximum, and therefore the pressure receiving plate 11 can be shifted to the resulating amount even with a small flow rate, and the apparatus becomes highest in its sensitivity. As the diameter or the number of the holes 11A is increased, the resistance value becomes smaller. Therefore, the shifting amount of the pressure receiving plate 11 is difficult to reach a regulating value even with a large flow rate, and the apparatus can measure a large flow rate. In this manner, the main body of the same shape can be used to obtain various kinds of devices of different full scales.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a flow rate conversion device suitable for measuring the flow rate of gas.

0002

[Prior Art] The present applicant has proposed a flow rate conversion device in ``Japanese Patent Application No. 62-91548'' or ``Japanese Patent Application No. 63-129882.'' These previously proposed flow rate conversion devices are of the cantilever type. The structure is such that the flow pressure of the fluid to be measured is applied to the pressure receiving plate, the amount of displacement of the pressure receiving plate is measured, and an electrical signal corresponding to the flow rate value is obtained.

In the previously proposed flow rate converter, in order to obtain a flow rate converter having measurement ranges for various flow rates, the opening area of the measurement hole provided to apply the flow pressure of the fluid to be measured to the pressure receiving plate must be increased. Alternatively, the measurement range is defined by changing the opening area of the hole constituting the bypass flow path.

0004

[Problem to be Solved by the Invention] When the measurement range is defined by changing the opening area of the measurement hole or by changing the opening area of the bypass hole, a flow rate conversion device is configured. There is a drawback that the number of types of flow rate converter bodies increases, which increases manufacturing costs. An object of the present invention is to propose a structure that allows a flow rate converter having a wide variety of measurement ranges to be obtained by using as few types of flow rate converter bodies as possible.

[0005]

[Means for Solving the Problems] The present invention provides a flow rate conversion device configured to apply the flow pressure of a fluid to be measured to a cantilever-shaped pressure receiving plate and measure the flow rate of the fluid from the amount of displacement of the pressure receiving plate. A hole is formed in the pressure receiving surface of the pressure receiving plate, and the diameter of the hole or the number of holes is selected to define the measurement range, or as another structure, the measurement range is defined by selecting the spring constant of the pressure receiving plate. It is a structure.

According to the structure of the present invention, it is possible to obtain a flow rate conversion device having different measurement ranges simply by changing the pressure receiving plate. Therefore, it is possible to manufacture various flow rate converters having different measurement ranges without having to prepare many types of main bodies, which has the advantage of reducing manufacturing costs.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a pressure receiving plate 11 which is the essential part of the present invention. In this invention, as one structure, holes 11A are provided on the pressure receiving surface of the pressure receiving plate 11, and the diameter or number of the holes 11A is selected to define the measurement range of the flow rate. Alternatively, as shown in FIG. 2, a splint 21 is provided on the pressure receiving plate 11,
Alternatively, the pressure receiving plate 11 may be formed into a tapered shape as shown in FIG. However, by varying the width W of the tapered tip, the spring constant of the pressure receiving plate 11 can be changed.

FIGS. 4 to 7 show the configuration of a flow rate conversion device using a cantilever-shaped pressure receiving plate 11. In FIGS. 4 to 7, 1 indicates an inlet of the fluid to be measured, and 2 indicates an outlet of the fluid to be measured. The fluid to be measured (gas) flows in the direction of arrow X. 3
and 4 are piping connectors, 5 is a flow rate conversion device main body, and 6 is a laminar flow plate. As shown in FIG. 5, the flow converter main body 5 has a wall 7 in the center, and a pair of crescent-shaped holes 8A, 8B are formed on both sides of the wall 7, and these holes 8A, 8B constitute a bypass path. . A measuring hole 9 is provided in the wall 7 through the wall 7.
is formed.

The measurement hole 9 has a slit shape, and this hole 9
There is a cantilever-shaped pressure receiving plate 11 shown in FIGS. 1 to 3 on the downstream side of the
is provided. This cantilever pressure receiving plate 11 is formed by a spring material made of magnetic material, and its displacement is determined by the detection coil 1.
Detected by 2. A compensation coil 13 is arranged on the other free end side of the pressure receiving plate 11 to perform zero balance compensation. Further, 14 indicates a stopper plate that protects the pressure receiving plate 11. The pressure receiving plate 11 and the stopper plate 14 are pressed and fixed by a restraining plate 19.

The laminar flow plate 6 is formed entirely into a flat plate, as shown in FIG. 6, for example, and this flat laminar flow plate 6
Hexagonal bypass hole 15 communicating with holes 8A and 8B
A and 15B are formed. Further, a hole 16 is formed on the downstream side of the measurement hole 9 provided in the flow rate conversion device main body 5. Furthermore, a fluid to be measured introduction hole 10 having an opening area larger than the opening area of the measurement hole 9 is provided on the upstream side of the measurement hole 9 of the flow rate conversion device main body 5.

Bypass hole 15A forming a bypass path
, 15B and the fluid to be measured inlet 10 are equipped with a large number of thin tubes 18 in order to make the fluid flow laminar. The inner 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. As described above, the pressure receiving plate 11 receives the flow pressure of the fluid to be measured flowing out from the measurement hole 9, and is displaced by an amount corresponding to the flow pressure. This amount of displacement is measured by a change in the current flowing through the detection coil 12, and is extracted as an electrical signal.

Here, a hole 11A is formed on the pressure receiving surface of the pressure receiving plate 11 as shown in FIG.
By appropriately selecting the number A, the resistance value of the pressure receiving plate 11 to the flow pressure can be changed. In other words, if the holes 11A are not formed on the pressure receiving surface of the pressure receiving plate 11, the resistance value of the pressure receiving plate 11 against the flow pressure becomes the maximum value, so the pressure receiving plate 11 can be displaced by a specified amount with a relatively small flow rate. . Therefore, a flow rate conversion device with the highest sensitivity can be obtained.

On the other hand, holes 11A are formed on the pressure receiving surface of the pressure receiving plate 11.
, and increase the diameter of this hole 11A, or
As the number of 1A increases, the resistance value of the pressure receiving plate 11 against the flow pressure becomes smaller, and even when the flow rate is large, the displacement amount of the pressure receiving plate 11 becomes difficult to reach the specified value. By utilizing this property, it is possible to construct a flow rate conversion device that measures a large flow rate.

As another method, as shown in FIG. 2, by attaching a splicing plate 21 to the pressure receiving plate 11 and preparing various spring constants of the splicing plate 21, the spring constant of the pressure receiving plate 11 can be substantially changed. can be changed. If the spring constant of the splicing plate 21 is made small, the pressure receiving plate 11 will be easily deflected, and a flow rate conversion device that can reach a specified displacement amount (full scale) with a relatively small flow rate can be obtained. Furthermore, if the spring constant of the splicing plate 21 is increased, the pressure receiving plate 11 becomes difficult to bend, and a flow rate conversion device that reaches a specified displacement amount with a large flow rate value can be obtained. Of course, various pressure receiving plates having different spring constants can be obtained by changing the thickness of the pressure receiving plate 11 itself without using the splicing plate 21.

Furthermore, as shown in FIG. 3, by making the shape of the pressure receiving plate 11 tapered and preparing various widths W of the tip portion with various sizes, a pressure receiving plate 11 equivalent to changing the spring constant can be obtained. be able to. Therefore, by attaching these various pressure receiving plates 11 to the flow rate converter main body 5 shown in FIG. 2, it is possible to obtain a flow rate converter having different full scale values. In other words, without changing the opening area of the measurement hole 9 and the opening area of the bypass holes 15A and 15B of the laminar flow plate 6, it is possible to obtain flow rate converters having various full scale values.

[0016]

As explained above, according to the present invention, pressure receiving plates 11 having different resistance values to the flow pressure of the fluid to be measured are prepared, or various pressure receiving plates 11 having different spring constants are prepared. By doing so, it is possible to obtain flow rate converters having various full scale values using the flow rate converter main body 5 and the laminar flow plate 6 having the same shape.

Therefore, a flow rate converter for small flow rates to a flow rate converter for large flow rates can be manufactured using the flow rate converter main body 5 and the laminar flow plate 6 of the same size. Therefore, it is not necessary to make the flow rate conversion device main body 5 and the laminar flow plate 6 with different dimensions, so that manufacturing costs can be reduced. Further, there is an advantage that manufacturing control can be easily performed.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the main part of the present invention.

FIG. 2 is a side view showing a modification of the main part of the invention.

FIG. 3 is a plan view showing a modification of the main part of the invention.

FIG. 4 is a sectional view for explaining the overall configuration of the flow rate conversion device according to the present invention.

FIG. 5 is a perspective view for explaining in detail the structure of the flow rate conversion device main body in the structure shown in FIG. 4;

FIG. 6 is a perspective view for explaining in detail the structure of the laminar flow plate in the structure shown in FIG. 4;

7 is a sectional view for explaining the mounting situation of the pressure receiving plate shown in FIGS. 1 to 3. FIG.

[Explanation of symbols]

1 Inlet of fluid to be measured 2 Outlet of measured fluid 3, 4 Piping fittings 5 Flow rate conversion device main body 6 Laminar flow plate 7 Wall 8A, 8B Hole 9 Measurement hole 10 Measured fluid introduction hole 11 Pressure receiving plate 11A Hole 12 Detection coil 13 Compensation coil 14 Stopper plate 15A, 15B Bypass hole 16 holes 21　　　　　Plate

Claims (3)

[Claims] [Claim 1] A. B. a measurement hole and a bypass hole provided in a flow path through which the fluid to be measured flows; a cantilever-shaped pressure receiving plate provided on the downstream side of the measurement hole and arranged so that the fluid that has passed through the measurement hole hits the plate surface in a direction substantially perpendicular to the plate surface;
C. D
．． A flow rate conversion device comprising: means provided on the pressure receiving plate and defining a flow rate measurement range. 2. The flow rate converter according to claim 1, wherein holes are formed in the pressure receiving surface of the pressure receiving plate, and the diameter or number of the holes is selected to define the flow rate measurement range. . 3. The flow rate converter according to claim 1, wherein the flow rate measurement range is defined by selecting a spring constant of the pressure receiving plate.