JP2016031331A - Flow rate resistance nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate resistance nozzle in which a flow rate value which is set during assembly is not changed.SOLUTION: A holder comprising a shank where a screw is cut on an outer peripheral face thereof and a body having diameter larger than outer diameter of the shank, on one end of the shank coaxially and integrally, has a continuity hole thereon which communicates the shank and the body and penetrates coaxially to a shaft center. Inner diameter of the continuity hole on the shank side is larger than inner diameter of the continuity hole on the body side, and a boundary therebetween has a step part having a surface vertical to the shaft center. A screw is cut on an inner peripheral face on the body side of the continuity hole. A screw-type nozzle comprises: a male screw having a screw part screwed to the screw on the continuity hole on the body side, and a head part disposed on the continuity hole on the shank side; and a tubing whose one end protrudes from the screw part to a penetration hole formed on the male screw coaxially to a center shaft, whose other end is inserted so as to locate in the head part. The tubing is crushed at a part projecting from the screw part, so that a flow rate value becomes a regulated flow rate value at regulated pressure, and an outer peripheral face of the tubing and an inner peripheral face of the penetration hole are fixed to each other in an air-tight state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flow resistance nozzle that is used, for example, to set a flow rate of a gas supplied at a predetermined pressure, or used as a leak amount reference device for flow rate calibration of a leak inspection apparatus.

  As a conventional flow resistance nozzle of this type, for example, a micro leak valve (hereinafter also referred to as a flow resistance nozzle) shown in Patent Document 1 is known. The structure includes a substantially cylindrical base 12, a metal block 13, and a protective tube 16, as shown in cross section in FIG. 8. The pedestal 12 is formed with a through hole 12 </ b> C at its axis. The metal block 13 has a female screw hole 12B coaxially formed with a diameter larger than the through hole 12C from one end side of the pedestal 12, and the metal block 13 has a male screw portion 13A screwed into the female screw hole 12B from one end. It protrudes and is formed with a male screw portion 13E at the other end.

  The thin tube 2 is mounted so as to penetrate through the thin tube through hole 13B formed in the axial center of the metal block 13 and both ends protrude, and the male screw portion 13A is coaxial with the thin tube through hole 13B and has a larger diameter than that. Female screw holes 13D are formed. A male screw that is screwed into the female screw hole 13D is cut to the outer periphery, and the tip of the cylindrical seal restrainer 7 through which one end of the thin tube 2 is inserted presses the ring-shaped sealing material 4 in the female screw hole 13D. Thus, the space between the outer peripheral surface of the thin tube 2 and the inner peripheral surface of the metal block 13 is sealed. A space between the outer peripheral surface of the metal block 13 and the inner peripheral surface of the pedestal 12 is sealed with a sealing material 14 and / or 15. Further, a filter 17 for removing dust is attached to one end of the through hole 12 </ b> C so as to face one end of the thin tube 2 protruding from the seal restrainer 7. A protective tube 16 that protects the protruding thin tube 2 is attached to the male screw portion 13E of the metal block 13, and a filter is provided at the tip of the protective tube 16 as necessary.

  In order to assemble this micro leak valve, first, the protective tube 16 is attached to the metal block 13, and the thin tube 2 is attached to the thin tube 2 with the ring-shaped sealing material 4 and the seal restrainer 7 attached to the thin tube 2. 13B, the seal material 4 is inserted into the female screw hole 13D, the seal restrainer is rotated and inserted into the female screw hole 13D, the seal material 4 is pressed, and the female screw hole of the base 12 on which the filter 17 is mounted. The male screw portion 13A of the metal block 13 is screwed into 12B. In the micro leak valve (flow resistance nozzle) of Patent Document 1 shown in FIG. 8, a screw hole 13C reaching from the outer peripheral surface to the narrow tube through hole 13B is formed in the metal block 13, and a specified flow rate value at a specified pressure. Then, the thin tube 2 can be crushed by the screw 6.

  FIG. 9 is a block diagram showing a basic configuration of a known leak inspection apparatus. An air pressure source 21 is connected to one end of a pipe 22 and a work 28 to be inspected is connected to the other end. In the pipe 22, a regulator 23, a flow meter 25, and an operation valve 26 are inserted in series in this order from the pneumatic pressure source 21 side. A pressure gauge 24 is connected to the pipe 22 between the regulator 23 and the flow meter 25, and a pressure gauge 27 is connected to the pipe 22 between the operation valve 26 and the work 28. In order to calibrate the flow rate value of the flow meter 25, the male screw pipe 12A of the base 12 of the micro leak valve of FIG. The regulator 23 is adjusted to supply a predetermined pressure of gas (for example, air), and the reading of the flow meter 25 is calibrated so that the leak amount from the minute leak valve at that time becomes a specified value.

Japanese Utility Model Publication No. 03-105773

  In the flow resistance nozzle of FIG. 8, when the flow rate of the thin tube 2 as a single part is measured in advance with another flow measurement device and the thin tube is crushed with a jig and set to a predetermined flow rate, the flow rate is set when the flow resistance nozzle is assembled. It is necessary to handle the tubule directly, and there is a possibility that the set flow rate is changed by bending the tubule by mistake. Therefore, the flow rate of the narrow tube as a single part in another flow rate measuring device is not set, but after the flow resistance nozzle is assembled as shown in FIG. doing. However, in this structure, since the flow rate is set to a predetermined value by crushing the thin tube 2 with the screw 6, the thin tube 2, the screw 6 and the metal block 13 after the setting are integrated with each other, and the flow resistance nozzle is assembled. At this time, if the metal block 13 is strongly tightened to the pedestal 12, the set flow rate value may change because the strain at the time of tightening is transmitted to the screw 6 in pressure contact with the thin tube 2. In such a case, it was necessary to disassemble the flow resistance nozzle, replace the thin tube 2 with a new one, set the flow rate again with the screw 6 and assemble the flow resistance nozzle.

  An object of the present invention is to provide a flow resistance nozzle in which the set flow rate does not change when the flow resistance nozzle is assembled.

In order to solve the above problems, the flow resistance nozzle according to the present invention is:
A shaft having a threaded outer peripheral surface and a body having a diameter larger than the outer diameter of the shaft at one end of the shaft are coaxially connected, and the shaft and the shaft center of the body communicate with each other. A through hole formed through the holder, the small diameter hole portion on the body side, and a large diameter hole whose diameter is larger than the small diameter hole portion on the shaft side than the small diameter hole portion. A step portion having a surface perpendicular to the shaft center at the boundary between the small diameter hole portion and the large diameter hole portion, and a screw is provided on the inner peripheral surface of the small diameter hole portion. Has been cut,
The screw part screwed into the small-diameter hole part and a head part having an outer diameter larger than the screw part arranged in the large-diameter hole part are integrated, and the screw part and the head part are passed through. A screw type nozzle having a male screw having a through-hole formed in the shaft center, a thin tube inserted into the through-hole, one end protruding from the screw portion, and the other end positioned in the through-hole, and the thin tube The outer peripheral surface and the inner peripheral surface of the through hole are airtightly fixed to each other, and the narrow tube is crushed at a portion protruding from the screw portion so as to have a predetermined flow rate,
Seal packing sandwiched between the head and the step of the conduction hole;
It is characterized by including.

  In the flow resistance nozzle according to the present invention, the thin tube in the portion protruding from the male screw of the screw type nozzle formed by inserting the thin tube into a through hole formed in a standard male screw and hermetically fixing is crushed to a predetermined flow rate. The seal packing is sandwiched between the head of the male screw and the step formed in the middle part of the conduction hole that penetrates the holder, so that the gap between the outer peripheral surface of the screw type nozzle and the inner peripheral surface of the conduction hole is reduced. Since the structure is airtight, even if the screw type nozzle is tightened to the holder, the distortion does not propagate to the protruding part from the male thread of the thin tube, so there is no possibility of changing the set flow rate when assembling the flow resistance nozzle, and accurate flow rate There is an effect that it is possible to assemble a flow resistance nozzle in which is set.

The flow resistance nozzle by 1st Example of this invention is shown, A is a side view, B is the front view which removed the filter and the filter holder in A, C is an axial sectional view in A. The screw type nozzle used for the flow resistance nozzle of this invention is shown, A is an axial sectional view, B is the front view seen from the head side of the screw type nozzle. A is a front view seen from the head side when a minus screw is used for the screw type nozzle, and B is a front view seen from the head side when a hexagon screw is used. FIG. 6 is an axial sectional view of a flow resistance nozzle according to a second embodiment of the present invention. FIG. 6 is an axial sectional view of a flow resistance nozzle according to a third embodiment of the present invention. FIG. 9 is an axial sectional view of a flow resistance nozzle according to a fourth embodiment of the present invention. Sectional drawing for demonstrating the fundamental structure of the flow resistance nozzle by this invention. An axial sectional view of a minute leak valve as a flow rate reference device according to the prior art. The basic block diagram of the conventional leak inspection apparatus.

  Hereinafter, embodiments of the present invention will be described in detail.

[First embodiment]
The flow resistance nozzle according to the first embodiment of the present invention will be described below. 1A shows a side view of the flow resistance nozzle, FIG. 1B shows a front view when a filter 52 and a filter retainer 54 described later with reference to FIG. 1C in FIG. 1A are removed, and FIG. 1C is along the axis in FIG. A cross section is shown. The flow resistance nozzle includes a holder 30, a screw type nozzle 40 mounted in the holder 30, a seal packing 51, a filter 52, and a filter holder 54. If necessary, a hose joint 60 and a packing 64 may be further included.

  In this first embodiment, the holder 30 is made of metal and is integrally formed in a hexagonal bolt shape, sharing the central axis thereof, protruding from the hexagon head 32 and one end surface of the hexagon head 32, and having an outer diameter smaller than the hexagon head 32. And a cylindrical portion 31 protruding from an end surface opposite to the axial portion 33 of the hexagonal head 32. The holder 30 is formed with a conduction hole 30b extending from one end to the other end coaxially with the central axis. The conduction hole 30b includes a conduction hole 33b on the shaft 33 side and a conduction hole 32b on the hexagonal head 32 side. In addition, the conduction hole 31b on the cylindrical portion 31 side has a coaxial communication with each other. The boundary between the conduction holes 32b and 33b does not have to be located at the boundary between the hexagonal head 32 and the shaft portion 33, and may be within the hexagonal head 32 or the shaft portion 33. Similarly, the boundary between the conduction holes 31b and 32b is It is not necessary to be located at the boundary between the cylindrical portion 31 and the hexagonal head 32, and may be located in the cylindrical portion 31 or the hexagonal head 32. However, for the sake of convenience, hereinafter, the conduction holes 31b, 32b, and 33b may be referred to as a conduction hole in the cylindrical portion 31, a conduction hole in the hexagonal head 32, and a conduction hole in the shaft portion 33, respectively. It can be said that the cylindrical portion 31 and the hexagonal head 32 constitute a body 312 of the holder 30, and the shaft portion 33 is formed to protrude from one end of the body 312.

  The inner diameter of the conduction hole 33b in the shaft portion 33 is set to be larger than the outer diameter of the head 41H of the male screw 41 constituting the screw type nozzle 40 described later. The inner diameter of the conduction hole 32b is smaller than the inner diameter of the conduction hole 33b, and the boundary forms a step 32s that forms a surface substantially perpendicular to the axial direction. The inner diameter of the conduction hole 31 b in the cylindrical portion 31 is larger than the inner diameter of the conduction hole 32 b in the hexagonal head 32. Screws are cut on the inner peripheral surfaces of the conduction holes 31b and 33b from the outer ends of the respective holes to an intermediate portion in the axial direction, and a screw that engages with the male screw 41 is axially provided on the inner peripheral surface of the conduction hole 32b. It is cut over almost the entire length.

  The screw type nozzle 40 has a male screw 41 and a thin tube 42 as shown in FIG. 2A in a cross section along the axial direction and in FIG. 2B a front view on the head side. A through hole 41h is formed coaxially with the central axis of the male screw 41, and a thin tube 42 is inserted into the through hole 41h. An adhesive is provided between the outer peripheral surface of the thin tube 42 and the inner peripheral surface of the through hole 41h. 43 is injected and airtightly fixed. The male screw 41 is formed by forming a through hole 41h along the axis of a commercially available standard male screw having a screw portion 41S and a head portion 41H. In the example shown in the figure, a pan screw having a cross hole 41c in the head portion 41H. An example using is shown. The inner diameter of the through hole 41h is smaller than the diameter of the inscribed circle at the center of the cross hole 41c, and one end of the through hole 41h is opened at the center bottom of the cross hole 41c. The end surface 41Hp on the screw portion 41S side of the head portion 41H forms a surface perpendicular to the central axis of the male screw.

  The thin tube 42 is, for example, a stainless steel tube, and one end of the thin tube 42 contacts the tip of the thin tube 42 when the male screw 41 is rotated by a driver and the screw type nozzle 40 is mounted in the conduction hole 30 b of the holder 30. The other end of the thin tube 42 protrudes from the screw portion 41S, and is located in the through hole 41h deeper than the center bottom of the cross hole 41c. The thin tube 42 is hermetically bonded and fixed to the male screw 41 with an adhesive 43 such as epoxy resin, silicon resin, or cyanoacrylate. Alternatively, without using an adhesive, the outer peripheral surface of the protruding portion of the thin tube 42 and the tip of the screw portion 41S are welded to substantially hermetically fix the outer peripheral surface of the thin tube 42 and the inner peripheral surface of the through hole 41h. May be. The screw-type nozzle 40 constructed in this manner is crushed precisely in any region of the protruding portion of the narrow tube 42 so that the flow rate of the narrow tube 42 becomes a predetermined value at a specified pressure by a flow rate adjusting device different from the present invention. The screw type nozzle 40 having such a flow rate set to a predetermined value can be prepared in advance for each desired different flow rate value.

  Returning to FIG. 1C, by turning the head portion 41H of the male screw 41 and screwing the screw portion 41S into the conduction hole 32b, the threaded portion 41S side end surface 41Hp of the head portion 41H and the step in the conduction hole 30b in the conduction hole 33b. The seal packing 51 is sandwiched between the portion 32s and pressed to seal between the outer peripheral surface of the male screw 41 and the inner peripheral surface of the conduction hole 30b. A disc-shaped filter 52 is mounted in the conduction hole 33b so as to come into contact with the head 41H of the male screw 41, and an annular filter retainer 54 whose outer periphery is threaded is screwed into the conduction hole 33b from the outside. . Accordingly, when pressurized gas higher than atmospheric pressure is supplied from the pneumatic source to the head 41H side of the screw-type nozzle 40, dust in the pressurized gas is removed by the filter 52, and the inner wall of the pore 42h of the narrow tube 42 is removed. Prevents from adhering to. The filter holder 54 may hold the filter 52 via an elastic O-ring 53.

  The shaft portion 33 of the holder 30 is replaced with, for example, the work 28 of the leakage inspection apparatus in FIG. 9 and screwed into the pipe 22, and the seal packing 34 mounted in the annular groove 32 g formed on the end face of the hexagonal head 32 is provided in the pipe 22. The flow resistance nozzle of the present invention is attached to a flow rate measurement system by being pressed and sealed to a flange (not shown) provided at the end of the flow rate. In this state, a pressurized gas (for example, air) having a specified pressure is supplied, and the reading of the flow meter 25 is calibrated so that the reading of the flow meter 25 at that time becomes the set flow rate value of the screw type nozzle 40. In the embodiment of FIG. 1, a case where a hose joint 60 is attached to the holder 30 in order to supply an outflow gas from the flow resistance nozzle to a desired system with a hose (not shown) is shown. The hose joint 60 has a cylindrical shape having a conduction hole 60 h on the central axis, a screw portion 63 that is screwed into a screw cut in the conduction hole 31 b of the holder 30, and a flange portion 62 having an outer diameter larger than that of the screw portion 63. And a connecting portion 61 to which the hose is connected. The seal packing 64 is sandwiched between the end surface of the flange portion 62 on the threaded portion 63 side and the end surface of the cylindrical portion 31 of the holder 30 to maintain airtightness.

  As described above, if the screw-type nozzle 40 having various flow values at a specified pressure is prepared in advance, the holder 30, the filter 52, and the filter retainer 54 are not replaced, and only the screw-type nozzle 40 has a desired flow rate value. Therefore, when a plurality of set flow values are required in advance, the cost of the flow resistance nozzle to be prepared can be reduced. On the other hand, in the case of the conventional flow resistance nozzle described with reference to FIG. 8, the thin tube 2 is set to a predetermined flow rate as one body with the metal block 13 and the seal presser 7, so that a number of different flow rates are set. When it is necessary, it is necessary to prepare a flow resistance nozzle as an individual product in which each flow rate is set, which is expensive.

  In the above-described embodiment, an example in which a pan-head screw having a cross hole is used as the male screw 41 is shown. However, as shown only in the top surface in FIGS. 3A and 3B, a minus screw having a slit groove 41d may be used. The bolt having 41e may be used, and the screw type may be a truss screw, a round screw, a flat screw, or the like in addition to the pan head screw. It is obvious that various other commercially available standard screws can be used with the through hole 41h.

[Second Embodiment]
FIG. 4 shows a second embodiment of the flow resistance nozzle according to the present invention. In the flow resistance nozzle according to the first embodiment described above, the supply side of the pressurized gas is limited to the shaft portion 33 side of the holder 30 provided with the filter 52, but in the flow resistance nozzle of the second embodiment, In addition, by providing a filter on the protruding end side of the thin tube 42, it can be used even when pressurized gas is supplied from the hose joint 60 side. As shown in FIG. 4, a spacer ring 71 is inserted into the conduction hole 31 b in the cylindrical portion 31 of the holder 30, and a filter 72 having an outer diameter larger than the inner diameter of the spacer ring 71 is opposed to the protruding tip of the narrow tube 42. The filter 72 is fixed to the side opposite to the spacer ring 71 by pressing the tip of the hose joint 60 through the elastic O-ring 73. The spacer ring 71 is for maintaining a predetermined distance between the protruding tip of the thin tube 42 and the filter 72. Since other configurations are the same as those in the first embodiment, the description thereof is omitted. According to the second embodiment, when the pneumatic pressure source is a negative pressure, the dust contained in the gas flowing into the flow resistance nozzle from the hose joint 60 side is removed by the filter 72, whereby the pores 42h (see FIG. 2A) can be prevented from adhering to the inner wall.

[Third embodiment]
In the flow resistance nozzles of the first and second embodiments described above, the case where the holder 30 is integrally formed is shown, but an embodiment of the flow resistance nozzle in which the holder is configured by two holder portions is shown in FIG. Show.

  In FIG. 5, a set of the outer holder portion 30A and the inner holder portion 30B corresponds to, for example, the holder 30 in FIG. 1C. The outer holder portion 30A has a cylindrical portion 31A, a hexagonal head portion 32A, and a shaft portion 33A having a smaller outer diameter than the holder portion 30 in FIG. 1C, and the shaft portion 33A has a screw as in FIG. 1C. A conduction hole 33Ab having an inner diameter larger than the head 41H of the mold nozzle 40 is formed. The cylindrical portion 31A and the hexagonal head portion 32A constitute a base portion 312A of the outer holder portion 30A. In the third embodiment, the conduction hole 33Ab has an inner diameter enlarged in the hexagonal head 32A to be a receiving hole (first enlarged hole part) 32Ab, and a screw hole (second enlarged hole part) in which the inner diameter is further enlarged in the cylindrical part 31A. ) 31Ab. No screw is cut on the inner peripheral surface of the accommodation hole 32Ab, and a screw is cut on the inner peripheral surface of the screw hole 31Ab.

  The inner holder portion 30B has a cylindrical portion 32B whose outer diameter is slightly smaller than the accommodating hole 32Ab, and a screw that is larger in outer diameter than the cylindrical portion 32B and is screwed into the outer peripheral surface of the screw hole 31Ab of the outer holder portion 30A. It has the cut screw part 31B. A conducting hole 32Bb is coaxially formed in the cylindrical part 32B, and the conducting hole 32Bb is a conducting hole 31Bb whose diameter is enlarged in the screw part 31B. A screw that engages with the screw portion 63 of the hose joint 60 is cut from the end surface side of the screw portion 31B on the inner peripheral surface of the conduction hole 31Bb. A screw into which a screw portion 41S (see FIG. 2A) of the screw type nozzle 40 is screwed is cut on the inner peripheral surface of the conduction hole 32Bb. An annular groove 32Bg is formed on the outer peripheral surface of the cylindrical portion 32B, and an elastic O-ring 35 is attached to the annular groove 32Bg. When the screw part 31B is screwed into the screw hole 31Ab of the outer holder part 30A and the inner holder part 30B is mounted in the outer holder part 30A, the cylindrical part 32B is accommodated in the accommodation hole 32Ab, and the outer periphery of the inner holder part 30B. The surface and the inner peripheral surface of the outer holder portion 30 </ b> A are sealed by an elastic O-ring 35.

  The end surface 32Bs of the cylindrical portion 32B is in contact with the stepped portion 32As at the boundary between the conduction hole 33Ab and the enlarged accommodation hole 32Ab, and in this state, the exposed portion of the end surface of the cylindrical portion 32B within the conduction hole 33Ab (step Part) 32Bs corresponds to the stepped part 32s in FIG. 1C. That is, the screw type nozzle 40 is screwed into the conduction hole 32Bb of the cylindrical portion 32B of the inner holder 30B so that the seal packing 51 is sandwiched between the end surface 41Hp (see FIG. 2A) of the head portion 41H and the step portion 32Bs. Yes. In this third embodiment, a set (including an elastic O-ring) of the base portion 312A (the cylindrical portion 31A and the hexagonal head portion 32A) of the outer holder 30A and the inner holder portion 30B is the body 312 in the first embodiment (FIG. 1A). , C). Further, the conduction holes 33Ab of the outer holder portion 30A and the conduction holes 32Bb and 31Bb of the inner holder portion 30B in the third embodiment correspond to the conduction holes 33b, 32b, 31b of the holder 30 in FIG. 1C, respectively. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

[Fourth embodiment]
In the third embodiment of FIG. 5, the filter 52 is disposed in the region where the shaft portion A is located in the conduction hole 32 </ b> Ab. It is difficult to construct a flow resistance nozzle having a small diameter shaft portion 33A. The same applies to the embodiment of FIG. 1C. The fourth embodiment of FIG. 6 enables the configuration of a flow resistance nozzle having a shaft portion with a small outer diameter. The conduction hole (reduction hole part) 33Ab of the shaft part 33A is smaller than the outer diameter of the head 41H (see FIG. 2A) of the screw-type nozzle 40 and the outer diameter of the filter 52. The conduction hole 33Ab is more detailed in the base 312A. Is a conduction hole 32Ab1 having an inner diameter slightly larger than the outer diameter of the head 41H and the outer diameter of the filter 52 in the hexagonal head 32A. In the following, like the embodiment of FIG. 5, the conduction hole 32Ab1 is an accommodation hole 32Ab2 whose inner diameter is further enlarged in the hexagonal head 32A. The conduction hole 32Ab1 corresponds to the conduction hole 33Ab in FIG. 5, and the accommodation hole 32Ab2 in FIG. 6 corresponds to the accommodation hole 32Ab in FIG. A step portion 33As is formed at the boundary between the conduction hole 33Ab and the enlarged conduction hole 32Ab1, and an O-ring 53 is mounted in the conduction hole 32Ab1 so as to be in contact with the step portion 33As. And a filter 52 is mounted.

  An O-ring 35 is attached to the annular groove 32Bg of the cylindrical part 32B of the inner holder part 30B, and the seal packing 51 is sandwiched between the end face (step part) 32Bs of the cylindrical part 32B and the head part 41H of the screw type nozzle 40. When the inner holder portion 30B is screwed into the outer holder portion 30A from the screw hole 31Ab side in a state where the screw type nozzle 40 is screwed into the conduction hole 32Bb, the end surface 32Bs of the cylindrical portion 32B comes into contact with the step portion 32As. In this state, the head portion 41H of the screw-type nozzle 40 is in a state in which the filter 52 is pressed against the step portion 33As via the O-ring 53 in the conduction hole 32Ab1. Other configurations are the same as those in FIG. The set of conduction holes 31Bb, 32Bb, 32Ab1, and 33Ab in FIG. 6 corresponds to the conduction hole 30b (set of 31b, 32b, and 33b) in FIG. 1C.

  According to the fourth embodiment, the inner diameter of the conduction hole 33Ab can be made smaller than the outer diameter of the filter 52 and the outer diameter of the head 41H of the screw-type nozzle 40, so that the outer diameter of the shaft portion 33A is compared with the case of FIG. Can be made smaller. When the holder 30 in FIG. 1C has an integral structure, it is necessary to insert the screw type nozzle 40 from the conduction hole 33b at the time of assembly. Therefore, the inner diameter of the conduction hole 33b is set to the outer diameter of the head 41H of the screw type nozzle 40. It cannot be made smaller. On the other hand, when the holder is constituted by the outer holder portion 30A and the inner holder portion 30B as shown in FIG. 6, it is not necessary to pass the screw type nozzle 40 through the conduction hole 33Ab during assembly, so that the inner diameter of the conduction hole 33Ab can be reduced. Therefore, the outer diameter of the shaft portion 33A can be reduced. Also in the third and fourth embodiments, a filter may be provided on the protruding end side of the narrow tube 42 as in the second embodiment.

[Basic structure of the invention]
The basic configuration of the present invention that applies to all the embodiments described above will be described with reference to FIG. The flow resistance nozzle according to the present invention includes a holder 30 having a body 312 and a shaft portion 33, a screw-type nozzle 40, and a seal packing 51. As shown in FIG. 2A, the screw type nozzle 40 has a thin tube 42 inserted through a through hole 41 h that passes through the central axis of the male screw 41, and the inner peripheral surface of the through hole 41 h and the outer peripheral surface of the thin tube 42 are hermetically fixed. In this state, a portion protruding from the screw portion 41S is crushed in advance so that a predetermined flow rate is obtained with a predetermined gas pressure. The holder 30 has a through hole 30b formed through the shaft portion 33 and the body 312. The through hole 30b is formed on the inner surface of a screw on which the screw portion 41S of the screw type nozzle is screwed on the body 312 side. The cut small-diameter hole portion 30b1 and the large-diameter hole portion 30b2 that accommodates the head 41H of the screw-type nozzle and has a larger inner diameter than the small-diameter hole portion 30b1 on the shaft 33 side. A seal packing 51 is sandwiched between a step 32s formed at the boundary between the small diameter hole 30b1 and the large diameter hole 30b2 and the head 41H of the screw type nozzle 40.

  As is clear from the description of the first to fourth embodiments described above, the holder 30 may be integrated or may be composed of two parts, an outer holder part and an inner holder part.

  As described above, the thin tube 42 is crushed so as to have a predetermined flow rate value at a portion protruding from the screw portion 41S of the male screw 41, and the screw type nozzle 40 having such a thin tube 42 is connected to the head of the male screw 41. 41H is screwed into the conduction hole 30b so as to press the seal packing 51 between the step 32s formed in the conduction hole 30b of the holder 30, so that any distortion at the time of mounting the screw type nozzle 40 into the holder 30 is achieved. However, the crushed portion formed in the protruding portion of the thin tube 42 is not affected.

  The present invention can be used for setting a predetermined flow rate in an arbitrary gas supply system or for flow rate calibration of a flow rate measuring device.

2: Thin tube 4: Seal material 7: Seal retainer 12: Base 13: Metal block 16: Protection tube 17: Filter 30: Holder 30b: Conductive hole 30A: Outer holder part 30B: Inner holder part 312: Body 32: Hex head 33: Shaft portion 32s: Step portion 40: Screw type nozzle 41: Male screw 41h: Through hole 41c: Cross hole 41H: Head portion 42: Narrow tube 43: Adhesive material 51: Seal packing 52: Filter 54: Filter presser 60: Hose Joint 72: Filter

Claims (7)

A shaft having a threaded outer peripheral surface and a body having a diameter larger than the outer diameter of the shaft at one end of the shaft are coaxially connected, and the shaft and the shaft center of the body communicate with each other. A through hole formed through the holder, the small diameter hole portion on the body side, and a large diameter hole whose diameter is larger than the small diameter hole portion on the shaft side than the small diameter hole portion. A step portion having a surface perpendicular to the shaft center at the boundary between the small diameter hole portion and the large diameter hole portion, and a screw is provided on the inner peripheral surface of the small diameter hole portion. Has been cut,
The screw part screwed into the small-diameter hole part and a head part having an outer diameter larger than the screw part arranged in the large-diameter hole part are integrated, and the screw part and the head part are passed through. A screw type nozzle having a male screw having a through-hole formed in the shaft center, a thin tube inserted into the through-hole, one end protruding from the screw portion, and the other end positioned in the through-hole, and the thin tube The outer peripheral surface and the inner peripheral surface of the through hole are airtightly fixed to each other, and the narrow tube is crushed at a portion protruding from the screw portion so as to have a predetermined flow rate,
Seal packing sandwiched between the head and the step of the conduction hole;
A flow resistance nozzle comprising:   2. The flow resistance nozzle according to claim 1, wherein the holder is integrally formed of metal. The flow resistance nozzle according to claim 1, wherein the holder includes:
The shaft portion and a base portion formed at one end of the shaft portion and having a larger diameter than the shaft portion are integrally formed. The large-diameter hole portion and the large-diameter hole portion on the opposite side to the shaft portion in the base portion A first enlarged hole whose diameter is enlarged at the end, and a diameter further enlarged at the end opposite to the shaft part of the first enlarged hole part, extending to an end opposite to the shaft part of the base, An outer holder part in which a second enlarged hole part threaded on the peripheral surface is formed of a coaxial core;
A cylindrical portion having an outer diameter smaller than the inner diameter of the first enlarged hole portion and larger than the inner diameter of the larger diameter hole portion, inserted into the first enlarged hole portion, and having the smaller diameter hole portion formed in the axis. And an outer diameter of the cylindrical portion opposite to the end of the shaft portion, a screw threaded into the second enlarged hole portion is cut on the outer peripheral surface, and a hole communicating coaxially with the small diameter hole portion. An inner holder part having a large-diameter screw part formed with,
An O-ring that is attached to an annular groove formed on the outer peripheral surface of the cylindrical portion, and seals between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the first enlarged hole portion;
The flow resistance nozzle, wherein the base and the inner holder portion constitute the body, and the end surface on the large-diameter hole side of the columnar portion constitutes the stepped portion.   The flow resistance nozzle according to any one of claims 1 to 3, wherein a filter is provided in the large-diameter hole portion so as to face the head portion, and the large-diameter hole portion extends to a tip of the shaft portion. A flow resistance nozzle which is extended and has a filter retainer mounted in the large-diameter hole on the side of the filter opposite to the head.   The flow resistance nozzle according to claim 3, wherein a filter mounted opposite to the head is provided in the large-diameter hole, and the large-diameter hole is on the opposite side of the filter from the screw-type nozzle. An inner diameter is made smaller than the outer diameter of the filter and is a reduced hole extending to the tip of the shaft, and a boundary between the larger diameter hole and the reduced hole is located in the base. Flow resistance nozzle.   The flow resistance nozzle according to any one of claims 1 to 3, wherein the conduction hole on the body side has a diameter from an intermediate portion in the axial direction to an end opposite to the shaft portion of the body from the small diameter hole portion. A flow resistance nozzle characterized by further including a filter mounted to be opposed to the protruding end of the narrow tube in a conducting hole having a large diameter on the body side and spaced from the protruding end of the thin tube.   The flow resistance nozzle according to any one of claims 1 to 6, wherein the outer peripheral surface of the thin tube and the inner peripheral surface of the through hole are airtightly fixed to each other by an adhesive.

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