JPH062156U - Laminar flow element - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a laminar flow element in which a flow path of a fluid can be mirror-finished extremely easily and at a low cost, and particles or impurities are not attached or accumulated. In the laminar flow element S provided in the bypass flow passage 4, one or a plurality of grooves 11 that are parallel and linear to the bypass flow passage S are formed on the outer surface of the columnar body 10 from one end side to the other end side thereof. Formed.

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. 4 (A), many thin tubes 31 are inserted into the outer tube 32, or as shown in FIG. A stack of a number of thin disks 34 having holes 33 formed therein (for example, Japanese Examined Patent Publication No. 1-40300), and as shown in FIG. 2C, a through hole 35 is formed at the center and A plurality of thin disks 37 radially provided with a communication groove 36 that connects the through hole 35 and the outer circumference are stacked to allow fluid to flow from the outer circumference of the disk 37 through the communication groove 36 to the through hole 35. (For example, Japanese Patent Laid-Open No. 50-2968). In addition, 38 and 39 in FIGS. 5B and 5C described above are positioning holes when the discs 34 and 37 are overlapped with each other.

[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.

However, in the laminar flow element shown in FIG. 4 (A), since a thin tube 31 having an extremely small inner diameter, for example, a tube having a diameter of about 0.2 mm is used, many of them are inserted into the outer tube 32. In addition to requiring a considerable amount of technology, it is difficult to polish the inside of each thin tube 31 to a mirror surface, and as a result, particles and impurities in the fluid adhere to the inside of the thin tube 31. is there.

Further, in the laminar flow device shown in FIGS. 4B and 4C, since a large number of discs 34 and 37 are laminated, circles other than the through holes 33 and 35 and the communication groove 36 are formed. A large number of fluid retention areas are likely to be formed at the contact areas between the plates, and particles and impurities tend to accumulate.

The present invention has been made in consideration of the above-mentioned matters. The purpose 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. The object is to provide a laminar flow element that does not adhere or stay.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, in a laminar flow element provided in a bypass flow passage, one groove that is parallel and linear to the bypass flow passage is formed on the outer surface of the column body from one end side to the other end side. Is formed.

Further, a plurality of the grooves may be provided independently of each other (not intersecting).

[0009]

[Action]

 In the laminar flow element, since the groove serving as a fluid flow path is formed on the outer surface of, for example, a cylindrical body, the groove can be polished to a mirror finish. Therefore, particles, impurities, etc. do not adhere or stay in the laminar flow element. In addition, it is possible to easily form the groove and finish it, and it is possible to obtain at low cost.

[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 flow meter incorporating a laminar flow element S according to the present invention. In this figure, 1 is a flow meter block, which is provided between a fluid inlet 2 and a fluid outlet 3. The bypass flow path 4 is provided with a laminar flow element S (the structure of which will be described later). 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 having excellent chemical resistance and corrosion resistance, such as stainless steel, and its outer surface. Is a line-symmetrical position from one end side to the other end side so that two grooves 11 each having a substantially rectangular cross-sectional shape are independent from each other and parallel to each other and to the bypass flow path 4. Is formed in.

The laminar flow element S configured as described above 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, since the groove 11 that serves as a fluid flow path is formed on the outer surface of the columnar body 10, it is easy to form the groove 11 and the groove 11 should be polished before the assembling. Since it can be manufactured and can be easily finished into a mirror surface state, it can be manufactured at low cost. As described above, since the groove 11 is mirror-polished, when the laminar flow element S is incorporated in the bypass flow path 4, particles, impurities, etc. may be attached or accumulated in the laminar flow element S. Therefore, the fluid flowing in the bypass flow path 4 can be favorably laminarized.

FIG. 3 shows another embodiment of the laminar flow device according to the present invention. In FIG. 3A, only one groove 11 is formed on the outer surface of the cylindrical body 10. ing. Further, in the structures shown in FIGS. 1B and 1C, a plurality of grooves 11 are formed in the outer surface of the columnar body 10 in line symmetry. Then, as shown in FIGS. 3D and 3E, when a plurality of grooves 11 are provided, their directions, shapes, and sizes do not necessarily have to be constant.

As described above, the number and direction of the grooves 11 are arbitrary. In addition to the rectangular shape, the cross-sectional shape of the groove 11 can be arbitrarily set, for example, V-shaped or U-shaped, and the size and number of the cross-sectional area of the groove 11 depends on the flow rate of the fluid flowing through the bypass passage 4. It goes without saying that it can be arbitrarily set according to the setting.

Further, instead of the cylindrical body 10, a prismatic body may be used, and some taper may be formed on the outer surfaces of these cylindrical bodies.

[0017]

[Effect of 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. Therefore, when this 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.

3 (A) to 3 (E) are views showing a groove formation mode in a laminar flow device according to another embodiment of the present invention.

4A to 4C are diagrams showing a conventional laminar flow element, respectively.

[Explanation of symbols]

S ... Laminar flow element, 4 ... Bypass channel, 10 ... Column, 11 ...
groove.

Claims (3)

[Scope of utility model registration request] 1. A laminar flow element provided in a bypass flow passage, wherein one outer groove of the column is formed with one straight and parallel groove to the bypass flow passage from one end side to the other end side thereof. Laminar flow element. 2. In a laminar flow element provided in a bypass flow passage, a plurality of grooves, which are parallel and linear to the bypass flow passage, are formed on the outer surface of the column body independently from each other from one end side to the other end side thereof. A laminar flow device characterized by the above. 3. The laminar flow device according to claim 1, wherein the columnar body is a cylinder.