JPH11117915A - Orifice for pressure type flow control device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain pressure flow control of high accuracy by providing an inlet tapered part, a short throttle parallel part, a short tapered part and a parallel diameter-enlarged part continuously in this order. SOLUTION: An orifice for a pressure type flow control device is composed of an orifice A, an inlet tapered part 1, a throttle parallel part 2, a tapered diameter-enlarged part 3 and a parallel diameter-enlarged part 4. As a concrete example, it is confirmed that linearity between a flow rate and primary pressure P1 is ensured over a range of the flow characteristic P2 /P1 of the orifice (a parallel diameter-enlarged part inner diameter (ϕ2 =0.2 mm) A being P2 /P1 =0.633 (P1 =3.0 kgf/cm<2> abs, P2 =1.89 kgf/cm<2> abs), that is, in spite of a form of the orifice A based on machining of only deburring by an R-cutting tool, a drill and a center drill, the linear characteristic of any orifice A is held to a point of P2 /P1 =0.633 so as to attain flow control of high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sonic nozzle (orifice) used in a pressure type flow control device for a fluid and a method of manufacturing the same, and is mainly used in a gas supply system of a semiconductor manufacturing facility. Things.

[0002]

2. Description of the Related Art Mass flow controllers have been used in many cases as flow control devices for gas supply systems in semiconductor manufacturing facilities, but pressure type flow control devices have recently been developed as an alternative to them. FIG. 20 shows a pressure type flow control device disclosed earlier by the inventor of the present application, in which the ratio P ₂ / P ₁ between the upstream pressure P ₁ and the downstream pressure P ₂ of the orifice 5 is determined by the gas criticality. in the state of being kept below the pressure ratio, the fluid flow rate Q of the orifice downstream Q = KP ₁
(Where K is a constant) is basically calculated (JP-A-8-338546). In FIG. 20, 1 is a pressure type flow control device, 2 is a control valve,
3 is a valve drive unit, 4 is a pressure detector, 5 is an orifice, 7 is a control device, 7a is a temperature correction circuit, 7b is a flow rate calculation circuit,
7c is a comparison circuit, 7d is an amplification circuit, 21a and 21b are amplification circuits, 22a and 22b are A / D conversion circuits, 24 is an inverting amplifier, 25 is a valve, Qy is a control signal, Qc is an operation signal, and Qs is a flow rate setting. Signal.

The above-mentioned pressure type flow control device can control the orifice upstream pressure P ₁ by controlling the opening and closing of the control valve 2 to control the orifice downstream flow Q with high accuracy, and is excellent in practical use. It is effective. However, there are still many problems to be solved in this pressure type flow control device, and in particular, a problem relating to a sonic nozzle (orifice) is an important problem.

First, the first problem is the cost of manufacturing the orifice. The diameter of the orifice is 10μmφ
~ 0.8mmφ may be required.
A sonic orifice having a fine diameter of 0 μmφ to 0.8 mmφ is usually formed by electric discharge machining or etching. However, when the orifice is formed into a predetermined shape by electric discharge machining or etching, for example, a shape specified in ISO 9300, there is a problem that the manufacturing cost of the orifice is extremely high.

[0005] The second problem is the variation in the flow characteristics of the orifice. A sonic orifice having a small diameter is difficult to work with, and its flow characteristics are hardly uniform within a predetermined range, and individual differences tend to be significantly increased. As a result, there is a problem that the accuracy of the flow rate measurement is deteriorated and that the calibration of the measured value takes too much trouble.

[0006] The third problem is a problem of the range of linearity on the flow characteristic curve. If the ratio P ₂ / P ₁ of the pressure P ₁ and the orifice downstream side pressure P ₂ upstream side of the orifice is less than the critical pressure ratio of gas (approximately 0.5 for air or nitrogen),
The gas flow velocity passing through the orifice becomes sonic and pressure fluctuations downstream of the orifice do not propagate to the upstream of the orifice.
It is said that a stable mass flow rate corresponding to the state on the upstream side of the orifice can be obtained. However, at the actual flow rate characteristic curve, the pressure ratio range where the so-called Riniya characteristics, i.e. pressure ratio range that can flow calculated as Q = KP ₁ becomes a low value far greater than the point of the critical pressure ratio, the more the flow rate There is a drawback that the controllable range is narrowed. Further, the linear characteristics themselves still have some problems, and it is difficult to obtain a high degree of linearity, so that it is difficult to further improve the control accuracy.

[0007]

SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problems in prior art orifices for pressure type flow controllers,
That is, (a) it is difficult to reduce the manufacturing cost of the orifice, and (b) it is difficult to process the orifice, and the variation in processing accuracy is directly linked to individual differences in the control flow rate, and high-precision and stable flow rate control cannot be performed. , (C) the pressure ratio range of the linear characteristic on the flow characteristic of the orifice is narrow,
It is intended to solve the problems that high-precision pressure flow control cannot be performed over a wide pressure ratio range, and that (d) it is difficult to further improve control accuracy because the linear characteristics are not advanced. Yes, processing can be performed relatively easily, manufacturing costs can be greatly reduced, and variations in flow characteristics are relatively small, and high-precision pressure flow control can be achieved over a wide pressure ratio range. An object of the present invention is to provide an orifice for pressure type flow control and a method of manufacturing the orifice.

[0008]

The invention according to claim 1 is characterized in that an inlet taper portion 1 formed by cutting one opening end of a pilot hole 6 formed in a main body member D to form an opening of a trumpet, A continuous short aperture parallel portion 2; a short tapered enlarged portion 3 continuous with the aperture parallel portion 2 formed by increasing the diameter of the other opening end of the pilot hole 6; 4 and; as the basic configuration of the invention.

According to a second aspect of the present invention, in the first aspect of the present invention, the inlet tapered portion 1 is formed as an inlet tapered portion formed by using a so-called radius tool whose inner wall surface is curved in a sectional view. According to a third aspect of the present invention, in the first aspect of the present invention, the inlet tapered portion 1 is an inlet tapered portion formed by using a so-called straight bite having a shape in which the inner wall surface is straight in a sectional view. It is.

According to a fourth aspect of the present invention, after drilling the pilot hole 6 from one side of the main body member D to the other side, the inside of the entrance portion on one side of the pilot hole 6 is cut with a cutting tool 1a to form a wrapper. A tapered inlet tapered portion 1 and a short drawn parallel portion 2 continuous with the inlet tapered portion 1 are formed, and then the pilot hole 6 is expanded from the other side surface of the main body member D by a drill drill 4a. The basic constitution of the present invention is to form a short tapered enlarged portion 3 continuous with the stop parallel portion 2 and a parallel enlarged portion 4 continuous with the tapered enlarged portion 3.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the cutting tool 1a forming the tapered portion 1 is a round tool or a straight tool.

The invention of claim 6 is the invention of claim 4 or claim 5.
In the invention according to the invention, the inlet tapered portion 1 and the constriction continuous therewith
After the parallel portion 2 is formed, the inside of the parallel portion 2 is
Diameter φ ₁The pilot hole 6 is expanded by the drill cone 2a having the same outer diameter as
Also, from the other side, a pilot hole 6
Before expanding the diameter of the drill, the center diameter is larger than the diameter of the drill bit 4a.
A hole at the other end of the pilot hole 6 having the diameter increased by the drill 7
After removing and further forming the tapered enlarged portion 3
From the other side, the inner diameter φ of the aperture parallel part 2₁The same outer diameter as
The other end of the parallel drawing part 2 on the other surface side by the drill cone 2a having
The part is deburred.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a pressure type flow control device orifice according to the present invention. In the drawing, A is an orifice, 1 is an inlet taper portion, 2 is a throttle parallel portion, 3
Is a tapered enlarged portion, and 4 is a parallel enlarged portion. The orifice A is made of stainless steel (SUS316L, FS9, etc.)
Round bars (diameter 8-11mmφ) and thin plates (thickness
mm), the inlet side (high pressure side of the fluid) B has a flat shape, and the outlet side (low pressure side of the fluid) C has a concave curved surface (partially spherical shell surface). Moreover the inner diameter phi ₁ of the orifice are respectively formed on 0.11Mmfai.

That is, the inlet tapered portion 1 has a radius of curvature R
Is formed on the curved surface of the mouth of the horn with a diameter of 0.22 mm, and the length L is 0.0
An aperture parallel part 2 of 5 mm is formed. The inner diameter φ ₁ of the aperture parallel portion 2 is selected to be 0.11 mmφ, and the aperture parallel portion 2 regulates the inner diameter of the orifice A.

The tapered enlarged portion 3 is formed continuously with the parallel portion 2 of the iris. In this embodiment, the shape of the tip blade (tip) of a drill for drilling with an outer diameter of 0.2 mmφ described later is used. The angle of inclination α determined by the angle of 120 ° is a tapered enlarged portion 3 having a slope of about 60 °. Furthermore, the parallel expanded diameter portion 4 is formed continuously with the tapered enlarged diameter portion 3, an inner diameter phi ₂ is selected to be 0.2 mm.

FIG. 2 shows another orifice A according to the present invention.
FIG. 3 shows an embodiment, and in this embodiment,
The inner tapered portion 1 has a straight inner wall surface in a sectional view.
Formed into a shape (ie, a conical tapered portion 1).
The inclination angle α_OIs selected to be 120 °. Ma
Orifice inner diameter φ₁Is 0.14mm, taper at entrance
Depth L of part 1₁= 0.25 mm, length L of aperture parallel part 2
= 0.05mm, inner diameter φ of parallel enlarged part 4_Two= 0.16m
m, inclination angle α = 60 °, tapered enlarged portion 3 and parallel enlarged portion
Length L with 4 _Two= 0.65 mm.

[0017] In the embodiment of FIGS. 1 and 2 have an orifice inner diameter phi ₁ and 0.1mmφ and 0.14mmφ but as the orifice according to the present invention, the inner diameter phi ₁ of about 10μmφ~0.9mmφ Things are best.

Next, a specific method of manufacturing the orifice for the pressure type flow control device according to the present invention will be described with reference to the manufacturing of the orifice A in FIG. 1 as an example. 3 to 9
, First, stainless steel (SUS316L, FS
9) or a thin plate (approximately 8 mm thick)
3 to 10 mm) to form a main body member D having a shape as shown in FIG. In addition, the outer surface B on the inlet side of the main body member D
Is flat, and the outer surface C on the outlet side is spherical (concave curved)
Are formed respectively.

After the formation of the main body member D, a center tapping having a shape as shown in FIG. That is, using a vertical tapping center machine, a so-called center fir is formed by a punch 5a having a sharp pointed tip made of an HSS material to form a center recess 5 having a triangular cross section as shown in FIG. In addition, punch 5a
Is 90 °, and the depth of the recess 5 is 0.1 mm.

Next, a carbide drill bit 6 of φ = 0.1 mmφ
As shown in FIG. 5, a hole is drilled inward from the center recess 5 as shown in FIG. 5 to form a pilot hole 6 as shown in FIG. Then, using a round tool 1a having a radius of curvature R = 0.22 mm having a shape as shown in FIG. 6, the entrance side of the prepared hole 6 in FIG. 5 is tapered, and a sectional view as shown in FIG. In this case, an inlet tapered portion 1 having a curved inner wall surface is formed. In the manufacture of the orifice A shown in FIG. 2, instead of the round tool 1a, the tip angle α _O
A straight bite (not shown) of 60 ° is used, and the inner wall surface forms a straight inlet tapered portion 1 (that is, a conical tapered portion) in a sectional view as shown in FIG.

Further, after the entrance taper portion 1 is formed, φ
= 0.11 mmφ is replaced with a drill cone 2a, and a hole of 0.11 mmφ is made from the fluid inlet side B to the fluid outlet side C. Thereby, the hole drilled by the drill cone 6a having a diameter of 0.1 mm is opened to a diameter of 0.11 mm.

Thereafter, the chucking direction of the main body member D is changed, and the drill is replaced with a center drill (outer diameter 0.3 mmφ × tip angle 90 °) 7 as shown in FIG. A hole of .11 mmφ is inserted inward from the outlet end of the hole by 0.05 mm from the edge of the blade, and a so-called burr remaining at the outlet end is removed.

When the deburring by the center drill 7 is completed, the parallel enlarged portion 4 having φ = 0.2 mmφ as shown in FIG. 9 is formed by a diameter expanding drill cone 4 a having an outer diameter of 0.2 mmφ and a tip angle of 120 °. Form. And finally, the drill bit 4
a is replaced with the drill bit 2a of φ = 0.11 mmφ, and burrs left at the boundary between the parallel drawing portion 2 and the tapered enlarged portion 3 are removed.

As described above, the orifice A of the present invention comprises a round tool 1a, a drill bit 6a having a diameter of 0.1 mm,
It is formed only by cutting, drilling, and deburring with a drill cone 2a having a diameter of 0.2 mm, a drill cone 4a having a diameter of 0.2 mm, and a center drill 7, and does not require a special polishing step or a drilling process such as electric discharge machining. That is, the orifice A according to the present invention is manufactured by an extremely simple process and at low cost.

FIG. 10 is a cross-sectional view of FIG.
Orifices (inner diameter of parallel enlarged part φ ₂ = 0.2mm)
3 shows the flow characteristics of A. As is clear from FIG. 10, P ₂ / P ₁ = 0.633 (P ₁ = 3.0 kgf
/ Cm ² abs, P ₂ = 1.89 kgf / cm ² ab
over a range of s), it is understood that the linear property between the flow rate and the primary side pressure P ₁ is secured well. That is, the orifice A formed by only the deburring by the round bit 1a, the drill cones 2a, 4a, 6a and the center drill 7
Despite formats are held its linear characteristic even in any of the orifices A to a point of P ₂ / P ₁ = 0.633, and has a high practical utility.

FIG. 11 shows flow rate-linearity error characteristics of three orifices A among the four orifices A according to the present invention. As is clear from FIG.
In the orifice, N is between + 0.66% and -0.41%.
Between + 0.74% and -0.42% for o2 orifice, and between + 0.69% and -0.43% for No3 orifice
It can be seen that they are sufficiently accurate for practical use. In addition, although there is a slight flow rate difference between the individuals, a proportional relationship is established between the pressure and the flow rate when P ₂ / P ₁ is in the range of about 0.633, and excellent linear characteristics ( That is, it can be seen that Q = KP ₁ ).

On the other hand, FIG.
Shows the flow rate characteristics of the specified sonic nozzle orifice.
One of the two is P_Two/ P₁= 0.60
(P ₁= 3.0 kgf / cm^Twoabs, P_Two= 1.9k
gf / cm^Twoabs) linearity is ensured over the range
But the other set is P_Two/ P₁= 0.533
Linearity can be secured only up to each orifice
It can be seen that there is a large difference between individuals. That is, the sound velocity
The wrench orifice is formed into a complicated shape through a polishing process, etc.
Is expensive and the production cost is extremely high
Nevertheless, there is a large variation in the individual differences in flow characteristics.
Some have good linear characteristics, while others have linear characteristics.
Practically fatal flaws, some of which are extremely bad
It turns out that it has. Further, FIG.
Pressure-flow linearity error of 12 sonic nozzle orifices
It shows the characteristic, and the linearity error is from + 0.72% to
-0.58% (No1 orifice) and + 0.72% ~
-0.52% (No. 2 orifice).

FIG. 14 significantly simplifies the machining work,
The main body D is pierced from the entrance side with a drill bit of = 0.11 mmφ, and the end face on the exit side is deburred by the center drill 7. In the case of the orifice shown in FIG. 13, although processing is simple and economical, the area where the linear characteristic in the flow rate characteristic can be ensured is P ₂ / P ₁ = 0.466 (P ₁ = 3 kgf / cm). ² a
bs, P ₂ = 1.39 kgf / cm ² abs), which has the drawback that linearity can be ensured only within a very narrow pressure ratio range. FIG. 15 shows the pressure-flow rate linearity error characteristic of the orifice in FIG. 14, and the linearity error is from + 1.69% to -1.02% (No.
1 orifice) and + 1.92% to -1.16% (No
2 orifices).

FIG. 16 shows the parallel expansion of the orifice A of the present invention.
The diameter portion 4 is expanded in two steps, and the diameter is increased in parallel.
4 has a first parallel enlarged portion 4a of φ = 0.2 mmφ and φ = 0.
A second parallel enlarged diameter portion 4b of 3 mmφ is formed.
In the orifice shown in FIG. 16, the number of processing steps is two.
(Deburring process at the end of 0.2mmφ hole and 0.3mm
φ drilling process) Despite the increase, linearity is maintained.
Holding range is P_Two/ P₁= 0.583 (P₁= 3kgf / c
m^Twoabs, P _Two= 1.75kgf / cm^Twoabs)
And is more linear than the case of the orifice A of the present invention.
There is a drawback that the range of securing characteristics is narrow. FIG.
Is the pressure-flow linearity error characteristic of the orifice in FIG.
The linearity error is between + 0.70% and-
0.49% (No1 orifice), + 0.59%-
0.41% (No2 orifice), + 0.70%-
0.48% (No. 3 orifice).

FIG. 18 shows a flow rate characteristic of the orifice A according to another embodiment of the present invention shown in FIG.
FIG. 19 shows a linearity error curve of the orifice flow rate of the orifice A shown in FIG.

The linearity error (FS.%) Is calculated by the least squares method based on a flow rate measurement curve actually measured within a set pressure range of 0 to 3.0 (kgf / cm ² · abs). An approximate straight line for the flow rate measurement curve that minimizes and equalizes the maximum plus difference and the maximum minus difference is obtained, and the difference between the approximate straight line value and the actually measured value is expressed in% of the maximum flow value. + 0.46% or less at the maximum for the forward fluid flow (the direction of arrow A in FIG. 2)
A linearity error of -0.45%, and a maximum of + 0.28% for the fluid flow in the opposite direction (the direction of arrow B in FIG. 2)
It has been found that a linearity error of -0.28% occurs, which significantly reduces the linearity error for fluid flow in the opposite direction.

[0032]

The orifice A of the present invention shown in FIG.
When comparing the orifices of FIGS. 12, 13 and 16, the orifice A of the present invention requires a very small number of orifice processing steps, and the processing is centered on cutting and drilling. There is no need for polishing or the like. As a result, the orifice A of the present invention can be made much cheaper than other types of orifices. This is the same in the case of the orifice A of the present invention shown in FIG. 2, and it can be manufactured at a very low cost as compared with other types of orifices.

The flow characteristics of the orifice A of the present invention can maintain the linearity between the flow and the primary pressure P ₁ over the range of P ₂ / P ₁ = 0.633. ,
In addition, the flow characteristic curves between the solids are almost the same.
That is, keeping the linear properties almost total number over a range of P ₂ / P ₁ = 0.633. As a result, correction of the flow rate Q of each orifice A is sufficient only by correction of the constant K at Q = KP ₁ , and adjustment of the flow characteristic of the orifice A becomes extremely simple. Further, the flow pressure characteristics of the orifice A of the present invention have excellent linearity, and the linearity error (FS.%) Is also + 0.74% to -0.4.
It is relatively low in the range of 1%, and can sufficiently withstand practical use.

Further, the orifice A of the present invention having a conical tapered portion shown in FIG. 2 has a higher linearity characteristic with less linearity error of the flow rate. Control becomes possible.

As described above, the present invention relates to a pressure type flow controller.
Orifices can be easily and inexpensively manufactured.
Perhaps relatively wide pressure ratio P_Two/ P₁Primary pressure over the range
Force P ₁And the flow can be maintained linearly.
Easy adjustment of flow characteristics (flow correction) between each individual
It has an excellent practical utility.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an orifice for a pressure type flow control device according to the present invention.

FIG. 2 is a partial longitudinal sectional view of an orifice for a pressure type flow control device according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a main body member forming an orifice A;

FIG. 4 is an explanatory view of a center tapping step of a processing step of an orifice A.

FIG. 5 is an explanatory view of a process of forming a parallel portion of a diaphragm.

FIG. 6 is an explanatory diagram of a round tool C used for forming an inlet tapered portion.

FIG. 7 is an explanatory view showing the formation of an inlet tapered portion and a throttle parallel portion.

FIG. 8 is an explanatory diagram of a deburring step using a center drill.

FIG. 9 is an explanatory view showing formation of a tapered enlarged portion and a parallel enlarged portion.

FIG. 10 shows an orifice A (φ = 0.11 m) according to the present invention.
(mφ).

FIG. 11 shows a flow rate-linearity error characteristic of the orifice in FIG.

FIG. 12 shows a flow rate characteristic of a sonic nozzle type orifice specified in ISO 9300.

FIG. 13 shows a flow rate-linearity error characteristic of the orifice in FIG.

FIG. 14 shows a flow rate characteristic of an orifice having a bore of φ = 0.11 mmφ, which simplifies processing.

FIG. 15 shows a flow rate-linearity error characteristic of the orifice in FIG.

FIG. 16 shows a flow rate characteristic of an orifice having two parallel-diameter enlarged portions.

FIG. 17 shows a flow rate-linearity error characteristic of the orifice in FIG. 16;

FIG. 18 is a flow rate characteristic curve of an orifice A having a conical inlet taper portion.

FIG. 19 is a flow rate / linearity error curve of an orifice A having a conical inlet taper portion.

FIG. 20 is a configuration diagram of a pressure type flow control device according to the prior application.

[Explanation of symbols]

A is an orifice, φ ₁ is the inner diameter of the parallel part of the throttle, φ ₂ is the inner diameter of the parallel enlarged part, D is the body member, B is the outer surface on the fluid inlet side,
C is a fluid outlet side outer surface, 1 is an inlet taper portion, 1a is a round tool, 2 is a throttle parallel portion, 2a is φ = 0.11 mm
φ drill bit, 3 is tapered enlarged part, 4 is parallel enlarged part,
4a is a drilling cone for φ = 0.2mmφ, 5 is a center recess, 5a is a punch for center tapping, 6 is a pilot hole, 6a is a drilling cone with φ = 0.1mm, 7 is a center drill, R is Radius of curvature of the entrance taper portion, L ₁ is the depth of the conical entrance taper portion, L is the length of the constriction parallel portion, α _O is the inclination angle of the conical entrance taper portion, α is the inclination angle of the tapered enlarged portion, L ₂ is the length of the tapered cone part and a parallel diameter portion.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tadahiro Omi 2-1-17-1, Yonegabukuro, Aoba-ku, Sendai, Miyagi Prefecture (72) Inventor Tetsu Kagazume 2381-2381 Kita-Shimojo, Fujii-machi, Nirasaki, Yamanashi Prefecture Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Kazuhiko Sugiyama 2381, Kita Shimojo, Fujii-machi, Nirasaki City, Yamanashi Prefecture Tokyo Electron Yamanashi Co., Ltd. (72) Inventor Osamu Fukada 2-3-2, Nobori, Nishi-ku, Osaka-shi, Osaka Fujikinnai Co., Ltd. (72) Inventor Susumu Ozawa 2-3-2, Noribori, Nishi-ku, Osaka-shi, Osaka Fujikin Co., Ltd. (72) Inventor Yoshihiro Sato 2-3-2, Noribori, Nishi-ku, Osaka-shi, Osaka Fujikinnai Co., Ltd. (72) Inventor Ryosuke Toi 2-3-2 Nobori, Nishi-ku, Osaka-shi, Osaka Fujikin Co., Ltd. (72) Inventor Tomi Uno Male 2-3-2, Noribori, Nishi-ku, Osaka-shi, Osaka Fujikin Co., Ltd. (72) Koji Nishino 2-3-2, Noribori, Nishi-ku, Osaka-shi, Osaka Fujikin Co., Ltd. (72) Hiroyuki Fukuda, inventor Osaka 2-3-2, Noribori, Nishi-ku, Osaka Fujikin Co., Ltd. (72) Inventor Shinichi Ikeda 2-3-2, Noribori, Nishi-ku, Osaka-shi Fujikin Co., Ltd. (72) Michio Yamaji Nishi-ku, Osaka, Osaka 2-3-3 Tachiboribori Fujikin Co., Ltd.

Claims (6)

[Claims] 1. An inlet taper portion (1) formed by cutting one opening end of a pilot hole (6) formed in a main body member (D) to form an opening of a trumpet, and a short throttle parallel to the inlet taper portion. A portion (2); a short tapered enlarged portion (3) continuous with the narrowed parallel portion (2) formed by increasing the diameter of the other opening end of the pilot hole (6), and a parallel portion connected thereto. An orifice for a pressure type flow control device, comprising: an enlarged portion (4); 2. The orifice for a pressure type flow control device according to claim 1, wherein the inlet taper portion (1) is an inlet taper portion having a curved inner wall surface in a sectional view. 3. The orifice for a pressure type flow control device according to claim 1, wherein the inlet taper portion (1) is an inlet taper portion having a shape whose inner wall surface is straight in a sectional view. 4. After drilling a pilot hole (6) from one side surface of the main body member (D) to the other side surface, the inside of the inlet on one side surface of the pilot hole (6) is cut with a cutting tool (1a). To form an inlet tapered portion (1) having the shape of a trumpet outlet and a short throttle parallel portion (2) continuous with the inlet tapered portion, and then the pilot hole (6) is expanded from the other side surface of the main body member (D). A pressure which is expanded by a diameter drill bit (4a) to form a short tapered enlarged portion (3) continuous with the narrowed parallel portion (2) and a parallel enlarged portion (4) continuous with the narrowed parallel enlarged portion (2). Of manufacturing an orifice for an air flow control device. 5. The method for manufacturing an orifice for a pressure type flow control device according to claim 4, wherein the bite (1a) forming the inlet tapered portion (1) is a round bite or a straight bite. 6. After forming an inlet tapered portion (1) and a constricted parallel portion (2) connected thereto, a drill bit having an outer diameter equal to the inner diameter (φ ₁ ) of the constricted parallel portion (2) from one side surface. 2
Before the diameter of the prepared hole (6) is expanded by a) and before the diameter of the prepared hole (6) is expanded from the other side by the drilling cone (4a) for expanding the diameter,
The other end of the prepared hole (6) on the other surface side is deburred by a center drill (7) having a diameter larger than the diameter drilling drill (4a), and the tapered enlarged portion (3) is formed. Later, from the other side, deburring of the end of the other side of the parallel part (2) with a drill bit (2a) having the same outer diameter as the inner diameter (φ ₁ ) of the parallel part (2). 6. The method for manufacturing an orifice for a pressure type flow control device according to claim 4, wherein the method is performed.