JP6534830B2 - Mass flow controller - Google Patents

Description

  The present invention relates to a mass flow controller used for fluid flow measurement and control.

  Patent Document 1 discloses a structure in which a flow rate sensor is attached to a body in which a flow path is formed. In Patent Document 1, a seal member and a spacer are interposed between a body and a sensor base of a flow rate sensor, and the sensor base is fixed to the body by bolts.

Japanese Patent Application Laid-Open No. 2-284772

  However, in the above flow rate sensor, since the entire lower surface of the sensor base is a flat surface, when the four corners of the sensor base are tightened by bolts, the four corners of the sensor base are tightened in contact with the spacer Therefore, by deforming so that the corners of the four corners of the sensor base bite into the spacer, the stress generated by tightening is absorbed at the four corners of the sensor base. As a result, stress is not transmitted to the portion of the sensor base in contact with the seal member, and the sealability between the flow sensor and the body is significantly reduced. In addition, in order to prevent inclination of the sensor base at the time of tightening and excessive tightening, it is desirable that the entire lower surface of the sensor base and the upper surface of the body be in contact when the tightening is completed. Therefore, the sensor base and the body can not be largely separated in advance to prevent the corners of the sensor base from coming into contact with the body.

  Then, an object of this invention is to provide the mass flow controller which improves the sealing performance between a flow sensor and a body significantly.

  In order to solve the above object, a mass flow controller according to an aspect of the present invention includes a body in which a fluid passage is formed, and a flow rate sensor fixed to the body and measuring a flow rate in the fluid passage. The flow rate sensor includes a sensor base supporting a thin tube through which fluid flows, and a fastening means for securing the sensor base to the body, and the sensor base is positioned to sandwich the base and the base. And a seal member pressing portion for pressing a seal member located between the base portion and the body, the base portion having a pair of end portions, between each end portion and the body, A relief space is formed to absorb the deformation of each end.

  Further, the relief space may be formed by providing a chamfer, a recess, or a notch at each end.

  The relief space may be formed by providing a recess in the body.

  A mass flow controller according to one aspect of the present invention includes a body in which a fluid passage through which a fluid flows is formed, and a flow rate sensor fixed to the body and measuring the flow rate of the fluid flowing in the fluid passage. The flow rate sensor includes a sensor base supporting a thin tube through which fluid flows, a spacer disposed between the sensor base and the body, and fastening means for securing the sensor base and the spacer to the body. And the sensor base has a base and a pair of ends positioned to sandwich the base, the base pressing a seal member located between the base and the body. Relief member for absorbing deformation of each end between each end and the body or the spacer or between the body and the spacer. There has been formed.

  The relief space may be formed by providing a chamfer or a recess at each end.

  Further, the relief space may be formed by providing a chamfer, a recess or a notch in the spacer.

  The relief space may be formed by providing a recess in the body.

  According to the present invention, it is possible to provide a mass flow controller that significantly improves the sealing performance between the flow rate sensor and the body.

1 shows an overall configuration of a mass flow controller according to an embodiment of the present invention. The cross section of a part of body and a flow sensor is shown. (A) Top view of a sensor base main body, (b) Bottom view, (c) Sectional drawing along the IIIc-IIIc line of (a), (d) A side view is shown. Sectional drawing along the IV-IV line of FIG. 2 is shown. The side view of the sensor base main body in a modification is shown. It is a figure corresponding to the sectional view of Drawing 4 in a modification. It shows a cross-sectional view of a part of a body and a flow rate sensor in a modification. The (a) top view and (b) side view of a spacer are shown. It is a figure corresponding to the sectional view of Drawing 4 in a modification. The top view of the spacer in which the notch was formed.

  A mass flow controller according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the upper and lower sides refer to the upper and lower sides of FIG.

  FIG. 1 shows the entire configuration of a mass flow controller 1 (hereinafter referred to as "MFC 1"). FIG. 2 shows a cross-sectional view of a part of the body 10 and the flow rate sensor 20.

  The MFC 1 mainly includes a body 10, a flow rate sensor 20, a control unit 3, and a flow rate control mechanism 4.

  The body 10 is made of a steel material such as stainless steel, and has a rectangular parallelepiped outer shape, and the joint 11 is attached to both end faces thereof. In the body 10, an inflow path 10a, a bypass flow path 10b, a sensor inflow path 10c, a sensor outflow path 10d, a combined flow path 10e, a valve chamber 10f, and an outflow path 10g are formed.

  The fluid that has passed through the inflow path 10a flows into the bypass flow path 10b. The sensor inflow path 10 c branches from the bypass flow path 10 b and causes the fluid to flow to the flow rate sensor 20. The sensor outflow path 10 d allows the fluid that has passed through the flow rate sensor 20 to flow out. In the combined flow path 10e, the fluid that has passed the bypass flow path 10b and the fluid that has passed the sensor outflow path 10d merge.

  Further, the bypass flow passage 10 b and the sensor inflow passage 10 c are configured such that fluid flows at a predetermined flow ratio (for example, 1: 2 to 1: 1000). A plurality of bypass sheets 12 are provided in the bypass flow passage 10b. The flow control valve 4A of the flow control mechanism 4 is disposed in the valve chamber 10f.

  Further, as shown in FIG. 2, a pair of countersunk portions 10i are formed on the sensor installation surface 10H of the body 10 in correspondence with the sensor inflow path 10c and the sensor outflow path 10d.

  The flow rate sensor 20 is a thermal type flow rate sensor, and includes a sensor base body 21, a thin tube 22, a pair of heating coils 23, a pair of sensor flanges 24, a sensor cover 25, a pair of gaskets 26, and fastening means. A certain four bolts 27 (only one is shown in FIGS. 1 and 2) are provided. The sensor base body 21 and the pair of sensor flanges 24 constitute a sensor base, and the sensor flange 24 corresponds to a seal member pressing portion.

  FIG. 3 shows (a) a top view, (b) a bottom view, a cross-sectional view taken along the line IIIc-IIIc of (c) and (a), and (d) a side view of the sensor base main body 21.

  The sensor base main body 21 is made of a steel material such as stainless steel, and has an outer shape of rectangular solid. The sensor base main body 21 has an abutment surface 21A that abuts on the sensor mounting surface 10H of the body 10, and a cover attachment surface 21B located on the opposite side to the abutment surface 21A and to which the sensor cover 25 is attached.

  Further, bolt insertion holes 21c are formed in the vicinity of the four corners of the sensor base main body 21, and flange insertion holes 21d are formed so as to be sandwiched between the two bolt insertion holes 21c. The flange insertion hole 21d has a large diameter portion 21d1 and a small diameter portion 21d2. Further, a pair of slits 21 e are formed in the sensor base main body 21 so as to pass through the respective flange insertion holes 21 d and the bolt insertion holes 21 a located on one side thereof and open at the end face of the sensor base main body 21 There is. Further, in the vicinity of each flange insertion hole 21d of the sensor base main body 21, a pin insertion hole 21f is formed. The portion in which the flange insertion hole 21d of the sensor base main body 21 is formed corresponds to the base 21K, and the portion in which the bolt insertion hole 21c is formed corresponds to the end 21L.

  Further, chamfered portions 21G are formed at four corners on the contact surface 21A side of the sensor base main body 21. Each chamfered portion 21G is formed, for example, by scraping a corner with a grinder. Each chamfered portion 21G is formed of a flank 21H located closer to the cover mounting surface 21B than the abutment surface 21A. Therefore, a relief space 21i is formed between the four corner portions of the sensor base main body 21 and the body 10 by each chamfered portion 21G.

  As shown in FIG. 1, the thin tube 22 is attached to the sensor base main body 21 in an inverted U-shape.

  The pair of heating coils 23 are wound around the thin tube 22.

  As shown in FIG. 2, each sensor flange 24 is made of steel such as stainless steel, has a substantially cylindrical shape, and is provided at each end of the thin tube 22. Each end of the thin tube 22 is inserted into the through hole 24 a of the sensor flange 24, and the thin tube 22 and each sensor flange 24 are connected by welding or the like.

  In the thin tube 22 and the sensor flange 24 connected, the thin tube 22 is inserted into the flange insertion hole 21 d through the slit 21 e of the sensor base body 21 and the bolt insertion hole 21 c, and the sensor flange 24 is disposed in the large diameter portion 21 d 1 The thin tube 22 and the sensor flange 24 are combined with the sensor base body 21.

  The sensor cover 25 is in the form of a box whose lower side is open, and as shown in FIG. 2, the spring pin 25A is connected to the sensor base body 21 by inserting it into the pin insertion holes 21f and 25b. The heating coil 23 is accommodated.

  The pair of gaskets 26 is made of a steel material such as stainless steel and has an annular shape. Further, each gasket 26 is disposed in the counterbore portion 10i and is located between the body 10 and the sensor flange 24. The thickness of the gasket 26 is larger than the depth of the counterbore portion 10i in the initial state. Each gasket 26 prevents the fluid flowing from the sensor inflow path 10 c into the capillary 22 or flowing out from the capillary 22 into the sensor outflow path 10 d from leaking between the body 10 and the flow rate sensor 20.

  FIG. 4 shows a cross-sectional view along the line IV-IV of FIG.

  As shown in FIG. 4, each bolt 27 is inserted into a bolt insertion hole 21 c of the sensor base body 21 and screwed to the body 10. Thereby, the flow rate sensor 20 is fixed to the body 10. By tightening each bolt 27, the gasket 26 is narrowed by the body 10 and the sensor flange 24 which is a seal member pressing portion to be compressed and deformed, and the contact surface 21A of the sensor base main body 21 contacts the sensor mounting surface 10H. Contact. On the other hand, the flank 21H of the chamfered portion 21G does not abut on the sensor mounting surface 10H. For this reason, the sensor base main body 21 is not bent.

  Based on the flow rate of the fluid measured by the flow rate sensor 20, the control unit 3 outputs a valve drive signal to the flow rate control mechanism 4 so that the fluid flowing through the bypass flow passage 10b has a predetermined flow rate.

  The flow control mechanism 4 drives the flow control valve 4A based on the valve drive signal from the control unit 3

  As described above, according to the mass flow controller 1 of the present embodiment, the relief spaces 21i are formed between the corners of the four corners of the sensor base main body 21 and the body 10 by the respective chamfers 21G. Therefore, the deformation of the four corners of the sensor base main body 21 is absorbed by the clearance space 21i, and the sensor base main body 21 is not bent. Therefore, since the sensor flange 24 of the sensor base does not float, the stress generated when the aforementioned bolts 27 tighten the sensor base body 21 and the body 10 is transmitted to the gasket 26. As a result, the sealing performance between the body 10 and the flow rate sensor 20 can be significantly improved.

  The present invention is not limited to the embodiments described above. Those skilled in the art can make various additions and modifications within the scope of the present invention.

  For example, as shown in FIG. 5, recess portions 21j may be formed at the four corners of the sensor base main body 21 instead of the chamfers 21G (FIG. 3D) to form relief spaces 21i. Further, as shown in FIG. 6, a recess 10j may be formed in a portion of the body 10 facing the four corners of the sensor base main body 21 to form a relief space 21i. Even with this configuration, the relief space 21i does not bend the sensor base body 21 and the sensor flange 24 of the sensor base does not float, so the sealing performance between the body 10 and the flow rate sensor 20 is significantly improved. It can be done.

  Further, as shown in FIG. 7, a spacer 5 may be interposed between the body 10 and the sensor base body 21. 7, the counterbore portion 10i is not formed in the body 10, and the gasket 26 is disposed on the sensor mounting surface 10H of the body 10 and in the gasket insertion hole 5b of the spacer 5. Further, the chamfered portion 21 </ b> G is not formed on the sensor base main body 21.

  FIG. 8 shows (a) a top view and (b) a side view of the spacer 5.

  As shown to Fig.8 (a), the spacer 5 is comprised with steel materials, such as stainless steel, and the external shape has comprised the rectangular parallelepiped shape. In the spacer 5, bolt insertion holes 5 a and gasket insertion holes 5 b are formed at positions corresponding to the bolt insertion holes 21 c and the flange insertion holes 21 d of the sensor base main body 21.

  Further, chamfered portions 5C are formed at the four corners of the spacer 5. Each chamfered portion 5C is formed, for example, by scraping a corner with a grinder. As shown in FIG. 9, a relief space 21i is formed between the four corner portions of the sensor base main body 21 and the spacer 5 by the respective chamfered portions 5C. Even if the chamfered portion 21G or the recess 21j is formed in the sensor base main body 21 without forming the chamfered portion 5C in the spacer 5, the four corner portions of the sensor base main body 21 and the spacer 5 In the meantime, a relief space 21i is formed. Even with this configuration, the relief space 21i does not bend the sensor base body 21 and the sensor flange 24 of the sensor base does not float, so the sealing performance between the body 10 and the flow rate sensor 20 is significantly improved. It can be done.

  Further, not the chamfered portion 5C but a recessed portion may be formed at the four corners of the spacer 5 to form the relief space 21i. Alternatively, the spacer 5 shown in FIG. 8B may be upside down and disposed between the body 10 and the sensor base main body 21 to form a relief space between the spacer 5 and the body 10 .

  Further, as shown in FIG. 10, notches 5 d may be formed at the four corners of the spacer 5 to form a relief space between the sensor base body 21 and the body 10. Alternatively, the recess 5 may be formed in the body 10 as shown in FIG. 6 without forming the chamfered portion 5C or the like in the spacer 5, and a relief space may be formed between the spacer 5 and the body 10. .

  In addition, although stainless steel is illustrated as a material of the body 10, the sensor base body 21, the sensor flange 24, the gasket 26 etc., usable materials (metal, non-metal according to the fluid to be controlled, the place of use, etc. In addition to the above, a resin material or the like may be included) or a shape. Moreover, although the bolt 27 was used as a fastening means, you may fix a sensor base to the body 10 by the other fastening means.

1: Mass flow controller, 5: Spacer, 5C: chamfer, 5d: notch, 10: body, 10j: recess, 20: flow sensor, 21: sensor base body, 21c: bolt insertion hole, 21G: chamfer , 21i: relief space, 21 j: recess, 21 K: base, 21 L: end, 22: capillary, 24: sensor flange, 26: gasket, 27: bolt

Claims (7)

A body having a fluid passage formed therein;
A flow rate sensor fixed to the body and measuring a flow rate in the fluid passage;
The flow rate sensor is
A sensor base supporting a capillary through which fluid flows;
Fastening means for securing the sensor base to the body;
The sensor base is
A base, and a pair of ends positioned to sandwich the base,
The base includes a seal pressing portion for pressing a seal located between the base and the body.
A mass flow controller, wherein a relief space is formed between each end and the body to absorb deformation of each end.   The mass flow controller according to claim 1, wherein the relief space is formed by providing a chamfer, a recess, and a notch at each end.   The mass flow controller according to claim 1, wherein the relief space is formed by providing a recess in the body. A body in which a fluid passage through which fluid flows is formed;
A flow rate sensor fixed to the body and measuring a flow rate of the fluid flowing in the fluid passage;
The flow rate sensor is
A sensor base supporting a capillary through which fluid flows;
A spacer disposed between the sensor base and the body;
Fastening means for securing the sensor base and the spacer to the body;
The sensor base is
A base, and a pair of ends positioned to sandwich the base,
The base includes a seal pressing portion for pressing a seal located between the base and the body.
A mass flow controller having a relief space formed between each end and the body or the spacer, or between the body and the spacer, for absorbing deformation of each end.   The mass flow controller according to claim 4, wherein the relief space is formed by providing a chamfer or a recess at each end.   The mass flow controller according to claim 4, wherein the relief space is formed by providing a chamfer, a recess, or a notch in the spacer. The mass flow controller according to claim 4, wherein the relief space is formed by providing a recess in the body.

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