JPH0525320U - Laminar flow element - Google Patents

Abstract

(57) [Abstract] [Purpose] The flow path of fluid can be mirror-finished very easily and inexpensively, particles and impurities do not adhere or stay, and the laminar flow has a long flow path. Providing an element. [Structure] A plurality of grooves 11 and 12 are formed in a spiral shape on the outer surface of a cylindrical body 10 independently of each other, and an outer cylindrical body 13 is fitted onto the cylindrical body 10.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is, for example, a laminar flow used as a bypass member in a flow meter (mass flow meter) or a fluid control device (mass flow controller) provided in a conduit through which a fluid such as gas or liquid used in a semiconductor manufacturing apparatus or the like flows. Regarding the element.

[0002]

[Prior Art]

 Conventionally, as the laminar flow element, as shown in FIG. 5 (A), a plurality of thin tubes 31 are inserted into an outer tube 32, or as shown in FIG. A stack of a large number of thin disks 34 forming the holes 33 (for example, Japanese Examined Patent Publication No. 1-40300), or as shown in FIG. A large number of thin disks 37 radially provided with communication grooves 36 that connect the holes 35 to the outer circumference are stacked, and fluid is allowed to flow from the outer circumference of the disks 37 through the communication grooves 36 to the through holes 35. (For example, Japanese Patent Publication No. 50-2968). In addition, 38 and 39 in FIGS. 5B and 5C are positioning holes when the discs 34 and 37 are superposed, respectively.

[0003]

[Problems to be solved by the device]

 By the way, in recent years, flowmeters, which are widely used in semiconductor manufacturing equipment, have undergone further microfabrication, and dust generation and gas adsorption / desorption from each component have become major problems. Mirror polishing is becoming an important issue. In a flow meter, etc., the flow rate of the laminar flow element becomes as close as possible to the flow path length of the measurement flow path in which the sensor coil is installed. It is known that the linearity improves, but it is also an important issue how to make it long in the restricted size (shape) of the flow meter.

However, in the laminar flow device shown in FIG. 5 (A), since a thin tube 31 having an extremely small inner diameter, for example, a tube of about 0.2 mm is used, many of these are inserted into the outer tube 32. However, it is difficult to mirror-polished the inside of each thin tube 31, and as a result, particles and impurities in the fluid adhere to the inside of the thin tube 31. There is.

Further, in the laminar flow element shown in FIGS. 5B and 5C, since a plurality of discs 34 and 37 are laminated, other than the through holes 33 and 35 and the communication groove 36. A large number of fluid retention parts are likely to be formed at the contact parts of the disks, and particles and impurities tend to accumulate.

In the prior art, if a long thin tube 31 is used, or if the number of disks 34, 37 to be laminated is increased, a long laminar flow element can be obtained. Although it can be obtained, there is a disadvantage that the entire laminar flow element becomes large.

The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to make it possible to mirror-finish a flow path through which a fluid flows extremely easily and at a low cost. It is an object of the present invention to provide a laminar flow element which has a long flow path length and which does not adhere or stay.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the laminar flow device according to the present invention has a plurality of grooves independently formed in a spiral shape on an outer surface of a cylinder or a cylinder, and the cylinder or the cylinder has an outer cylinder. It is configured to fit on the outside.

[0009]

[Action]

 In the laminar flow element, since the groove serving as a fluid flow path is formed on the outer surface of the cylindrical body or the cylindrical body, the groove is ground before the outer body is fitted onto the cylindrical body or the cylindrical body. It can be polished to a mirror finish. Therefore, particles, impurities, etc. do not adhere or stay in the laminar flow element. Further, the polishing finish can be performed easily and inexpensively. Further, since the groove is formed in a spiral shape on the cylindrical body or the outer surface of the cylindrical body, the flow path formed by the groove is longer than the actual length of the cylindrical body, and therefore as a laminar flow element. A long flow path can be obtained without increasing the outer dimensions of the.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

First, FIG. 2 shows a main part of a flowmeter incorporating a laminar flow element S according to the present invention. In this figure, 1 is a flowmeter block, and its fluid inlet 2 and fluid outlet 3 A laminar flow element S (the structure of which will be described later) is provided in the bypass flow path 4 between and. Reference numeral 5 is a measurement flow path provided in parallel with the bypass flow path 4, and is provided so as to connect between the openings 6 and 7 opened on the upstream side and the downstream side of the laminar flow element S, and its horizontal portion. Two sensor coils 9 as constituent elements of a bridge circuit (not shown) are wound around the outer periphery of 8 at appropriate intervals.

Next, an example of the structure of the laminar flow element S will be described with reference to FIG. 1. Reference numeral 10 is a cylindrical body made of metal such as stainless steel having excellent chemical resistance and corrosion resistance. Then, on the outer surface of the cylindrical body 10, from one end side to the other end side, two grooves 11 and 12 having, for example, V-shaped cross-sections are spirally formed independently of each other and have the same length. Is formed. Reference numeral 13 denotes a cylindrical outer tubular body made of, for example, stainless steel to which the cylindrical body 10 is fitted, and its inner diameter is set to be slightly larger than the outer diameter of the cylindrical body 10, and one end side thereof is large. It is formed on the diameter portion 14.

Then, the cylindrical body 10 in which the grooves 11 and 12 are formed is press-fitted into the outer tubular body 13, so that between the cylindrical body 10 and the outer tubular body 13, independent grooves 11 and 12 are formed. The two laminar flow paths are formed, and thus the laminar flow element S is formed. The laminar flow element S thus formed can be easily incorporated in the bypass flow path 4 of the flow meter block 1 as shown in FIG.

In the laminar flow element S, the grooves 11 and 12 serving as fluid flow passages are formed on the outer surface of the cylindrical body 10. Therefore, the grooves 11 and 12 can be polished prior to the press-fitting, and are easy and inexpensive. It can be mirror-finished. As described above, since the grooves 11 and 12 are mirror-polished, particles and impurities do not adhere to or stay in the laminar flow element S. Since the grooves 11 and 12 are spirally formed on the outer surface of the cylindrical body 10, the flow path formed by the grooves 11 and 12 is longer than the actual length of the cylindrical body 10, and therefore, A long flow path can be obtained without increasing the outer dimensions of the laminar flow element S.

Then, for example, in the conventional laminar flow element shown in FIGS. 5 (A) to 5 (C), the length of the flow path was at most 2 to 3 cm, but according to this embodiment, It has become possible to easily obtain a flow path having a flow rate of three times or more without enlarging the laminar flow element S. Therefore, when such a laminar flow element S is incorporated in, for example, a flow meter, the length of the bypass section (laminar flow element S) can be made equal to the length of the measurement flow path 8, and thereby the measurement can be performed. The diversion ratio between the flow path 8 and the bypass section becomes accurate, the ratio between the flow rate and the sensor output, that is, the linearity is greatly improved, and the measurement accuracy of the flow meter is greatly improved.

3 (A) and 3 (B) show another embodiment of the present invention. In this embodiment, eight grooves 16 having the same sectional shape are independently formed on the outer surface of the cylindrical body 15. It is provided in a spiral shape in this state to allow a large flow rate. In this figure, 17 is an outer tube.

In the above-mentioned embodiment, the grooves 11, 12 and 16 which serve as the flow paths are formed on the outer surfaces of the cylindrical bodies 10 and 15, but instead of this, they have an appropriate thickness. It may be formed on the outer surface of the cylindrical body.

4 (A) and 4 (B) show another embodiment of the present invention. In this embodiment, a plurality of grooved cylinders are stacked to accommodate a larger flow rate. I am doing so. That is, in this figure, a plurality of grooves 19 are provided on the outer surface of a cylindrical body 18, a plurality of grooves 21 are provided on the outer surface of a cylindrical body 20 on which the cylindrical body 18 is fitted, and the cylindrical body 20 is A plurality of grooves 23 are provided on the outer surface of the cylindrical body 22 to be fitted, the cylindrical body 20 is fitted to the cylindrical body 18, and the cylindrical body 22 is fitted from the outside. Needless to say, the grooves 19, 21, and 23 are formed in the columnar body 18, the cylindrical body 20, and the cylindrical body 22 in a spiral shape independently of each other. Also, in this figure, 24 is an outer tube.

The respective grooves 11, 12, 16, 19, 21, 23 do not need to have the same cross-sectional shape or equal length, and can be set arbitrarily.

[0020]

[Effect of the device]

 As described above, according to the present invention, it is possible to provide a clean laminar flow element in which the flow path of the fluid can be mirror-finished extremely easily and at a low cost, and particles and impurities are not attached or accumulated. Obtainable. In addition, since a laminar flow element having a long flow path can be obtained, when it is incorporated into a flow meter or a fluid control device, a device with good linearity can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of a laminar flow device according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a main part of a flow meter incorporating the laminar flow element.

FIG. 3 illustrates a laminar flow device according to another embodiment of the present invention,
(A) is a perspective view showing a main part of the laminar flow element, and (B) is a longitudinal sectional view of the laminar flow element.

4A and 4B show a laminar flow device according to still another embodiment of the present invention, wherein FIG. 4A is a perspective view showing an essential part of the laminar flow device, and FIG. 4B is a vertical sectional view of the laminar flow device.

5 (A), (B), and (C) are diagrams showing a conventional laminar flow element, respectively.

[Explanation of symbols]

10, 15, 18… Cylinder, 20, 22… Cylinder, 11, 12, 16, 1
9, 21, 23 ... Groove, 13, 17, 24 ... Outer cylinder.

Claims (1)

[Scope of utility model registration request] 1. A structure in which a plurality of grooves are independently formed in a spiral shape on an outer surface of a cylindrical body or a cylindrical body, and an outer cylinder body is externally fitted to the cylindrical body or the cylindrical body. Characteristic laminar flow element.