JP2013170668A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint, with which excessive deformation or damaging of a pipe is suppressed to suppress degradation in quake resistance, while increase in execution procedure is suppressed.SOLUTION: A pipe joint includes: a joint body 1 in which a metal pipe 5 to be connected is inserted; a nut 2 fastened to the joint body 1 through the pipe 5; a front ferrule 3 interposed between the joint body 1 and the nut 2, having a tip part formed in a shape of a wedge is pressed against the joint body 1 by a fastening force of the nut 2; and a back ferrule 4 interposed between the front ferrule 3 and the nut 2, having a tip part formed in a shape of a wedge is pressed against the front ferrule 3 by the fastening force of the nut 2. Contact parts of the front ferrule 3 and the back ferrule 4 which are in contact with the pipe 5 are made of material softer than material of the pipe 5.

Description

  The present invention relates to a pipe joint for connecting pipes.

  As one of the pipe joints, there is a double ring biting pipe joint including a joint body, a nut, a front ferrule, and a back ferrule. In a double ring bite pipe joint, the nut and the joint body are inserted by inserting the pipe into the joint body and interposing the front ferrule and back ferrule between the joint body and the nut and tightening the nut against the joint body. The back ferrule and the front ferrule are pressed against each other, and the ferrule is pressure-bonded to the pipe to ensure airtightness (see Patent Documents 1 and 2).

Japanese Patent Application No. 11-325342 Japanese Patent Application No. 2009-150503

  In the joint of the above-mentioned Patent Document 1, since the tip of the ferrule formed at an acute angle is bitten into the pipe and the pipe is connected, a sharp notch can be formed on the pipe surface, or the pipe can be excessively deformed to form a thin-walled portion. . For this reason, there is a problem in that a weak portion is generated in the pipe, and the seismic resistance against vibration due to the working fluid is likely to be lowered.

  On the other hand, since the joint of Patent Document 2 is processed at the tip of the pipe at the time of construction to create a groove as a ferrule fixing part, deformation of the joint is suppressed, but the construction procedure increases and the burden on the installer increases. In addition, in order to use the joint, a thin wall portion of the pipe is intentionally formed by forming a groove at the tip portion of the pipe, and there is a possibility that stress due to vibration is concentrated on the groove portion.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pipe joint that can suppress an excessive deformation and damage of a pipe while suppressing an increase in construction procedures, and can suppress a decrease in earthquake resistance. And

  In order to achieve the above object, a first invention includes a joint body into which a metal pipe to be connected is inserted, a nut fastened to the joint body through the pipe, and between the joint body and the nut. A front ferrule in which a tip portion formed in a wedge shape is pressed against the joint body by a fastening force of the nut, and a tip portion formed in a wedge shape is interposed between the front ferrule and the nut. A back ferrule that is pressed against the front ferrule by a fastening force of the front ferrule, and a contact portion between the front ferrule and the pipe of the back ferrule is formed of a material softer than a material of the pipe. .

  In a second aspect based on the first aspect, the front ferrule includes a front seal portion that comes into contact with the pipe, and a metal front ring portion that restrains the seal portion together with the joint body and the pipe. It is characterized by being.

  In a third aspect based on the second aspect, the back ferrule includes a back seal portion that contacts the tube, and a back ring portion that restrains the back seal portion together with the front ring portion and the tube. It is characterized by that.

  According to a fourth aspect, in the third aspect, the front seal portion and the back seal portion are made of a fluororesin.

  According to a fifth invention, in the fourth invention, in a state before the nut is fastened, the angle of the front end portion of the front ferrule with respect to the outer peripheral surface of the pipe is a notch portion of the joint body into which the front end portion enters. Is smaller than an angle with respect to the outer peripheral surface of the tube.

  According to a sixth invention, in the fourth invention, in the state before the nut is fastened, the angle of the tip portion of the back ferrule with respect to the outer peripheral surface of the tube is a notch portion of the front ferrule into which the tip portion enters. Is smaller than an angle with respect to the outer peripheral surface of the tube.

  ADVANTAGE OF THE INVENTION According to this invention, the excessive deformation | transformation and damage of a pipe | tube can be suppressed and the fall of earthquake resistance can be suppressed, suppressing the increase in a construction procedure.

It is an axial sectional view of the state after completion of construction of a pipe joint concerning one embodiment of the present invention (after tightening). It is sectional drawing of the axial direction of the state before construction (before tightening) of the pipe joint which concerns on one embodiment of this invention. It is sectional drawing of the axial direction of the state attached to the pipe | tube of the ferrule which comprises the pipe joint which concerns on one embodiment of this invention.

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

  1 is an axial sectional view of a pipe joint according to an embodiment of the present invention after completion of construction (after tightening), FIG. 2 is an axial sectional view of the state before construction (before fastening), and FIG. FIG. 3 is an axial sectional view of a ferrule attached to a pipe. In the following description, the right side in these figures is the front side, and the left side is the rear side.

  As shown in FIGS. 1 to 3, the pipe joint of the present embodiment is a so-called double ring biting pipe joint, and includes a joint body 1, a nut 2, a front ferrule 3 and a back ferrule 4.

  The joint body 1 has an insertion portion 1a into which a metal pipe 5 to be connected is inserted, a male screw portion 1b into which a nut 2 is screwed, and a notch portion 1c to which the front ferrule 3 is pressed. The notch 1 c increases in distance from the outer peripheral surface of the pipe 5 as it approaches the rear end surface of the joint body 1 from the front end portion in contact with the outer peripheral surface of the pipe 5. Create a gap.

  The nut 2 is fastened to the joint main body 1 with the pipe 5 being passed through the inner side. The nut 2a is screwed into the male thread 1b of the joint main body 1, and the ring 5 surrounds the pipe 5 in front of the female thread 2a. The press chamber 2b which is a space of

  The front ferrule 3 is a ring-shaped member that allows the pipe 5 to pass through the inner periphery thereof, and is interposed between the joint body 1 and the nut 2, strictly between the joint body 1 and the back ferrule 4, and is shown in FIG. 3. Thus, a front seal portion 3a and a front ring portion 3b are provided. The front seal portion 3a is a portion that comes into contact with the outer peripheral surface of the tube 5 and enters the notch portion 1c of the joint body 1, and the tip portion (front end portion) is inclined to rise obliquely from the outer peripheral surface of the tube 5 toward the rear side. It is formed in a wedge shape with a surface. The material of the front seal portion 3a, which is the contact portion of the front ferrule 3 with the tube 5, is formed of a softer material than the material of the tube 5 (for example, copper). In particular, the front seal portion 3a in the present embodiment is Made of fluororesin. In addition, in the state before the nut 2 is fastened as shown in FIG. 2, when viewed in an axial section, the angle α of the front end portion of the front seal portion 3 a of the front ferrule 3 with respect to the outer peripheral surface of the pipe 5 is The angle β of the cutout portion 1c of the main body 1 with respect to the outer peripheral surface of the tube 5 is smaller than the angle β.

  The front ring portion 3b is made of metal, and the nut 2 is fastened to the joint body 1 and the front seal portion 3a is pressed against the notch portion 1c of the joint body 1 by the fastening force of the nut 2 (state shown in FIG. 1). ), The front seal portion 3a is sealed and restrained together with the notch portion 1c and the pipe 5 of the joint body 1. In the present embodiment, the front ring portion 3 b is made of stainless steel, like the joint body 1 and the nut 2. A notch 3c against which the back ferrule 4 is pressed is provided at the rear of the front ring portion 3b. The notch 3c increases the distance from the outer peripheral surface of the tube 5 as it approaches the rear end surface of the front ferrule 3 from the front end portion in contact with the outer peripheral surface of the tube 5, Create a gap.

  Similarly to the front ferrule 3, the back ferrule 4 is a ring-shaped member that allows the pipe 5 to pass through the inner periphery thereof. The back ferrule 4 is interposed between the front ferrule 3 and the rear wall surface of the pressing chamber 2b of the nut 2, as shown in FIG. A back seal part 4a and a buckling part 4b are provided. The back seal portion 4 a is a portion that contacts the outer peripheral surface of the tube 5 and enters the notch portion 3 c of the front ferrule 3, and the tip portion (front end portion) is inclined to rise obliquely from the outer peripheral surface of the tube 5 toward the rear side. It is formed in a wedge shape with a surface. The material of the back seal part 4a, which is the contact part of the back ferrule 4 with the pipe 5, is formed of a softer material than the material of the pipe 5 (for example, copper). In particular, the back seal part 4a in the present embodiment is Made of fluororesin. In addition, in the state before the nut 2 is fastened as shown in FIG. 2, when viewed in the axial cross section, the angle γ of the distal end portion of the back seal portion 4a of the back ferrule 4 with respect to the outer peripheral surface of the tube 5 is The angle δ of the notch 3c of the ferrule 3 with respect to the outer peripheral surface of the tube 5 is made smaller. The buckling portion 4b is made of metal, and the nut 2 is fastened to the joint body 1 and the back seal portion 4a is pressed against the notch 3c of the front ferrule 3 by the fastening force of the nut 2 (the state shown in FIG. 1). ), The back seal portion 4a is sealed and restrained together with the notch portion 3c and the tube 5 of the front ferrule 3.

  When the pipe 5 is connected using the pipe joint having the above-described configuration, the pipe 5 is first passed through the nut 2, the back ferrule 4 and the front ferrule 3, and in this state, the pipe 5 is inserted into the insertion portion 1a of the joint body 1 as shown in FIG. Insert into. Thereafter, by tightening the nut 2 into the joint body 1, the rear surface of the pressing chamber 2 b of the nut 2 pushes the back ferrule 4, the back ferrule 4 pushes the front ferrule 3, and the back ferrule 4 and the front ferrule 3 are joined to the joint body 1. And the nut 2. As a result, the tip of the back seal portion 4a of the back ferrule 4 enters the cutout portion 3c of the front ferrule 3 as shown in FIG. 1, and is deformed by being restrained by the front ferrule 3 and the back ring portion 4b. Pressed against the outer peripheral surface. Further, the front end portion of the front seal portion 3a of the front ferrule 3 enters the notch portion 1c of the joint main body 1 as shown in the figure, and is deformed by being restrained by the joint main body 1 and the front ring portion 3b to be deformed. Pressed against the surface.

  As described above, the angles α and γ at the front end portions of the front seal portion 3a and the back seal portion 4a are smaller than the angles β and δ of the cutout portions 1c and 3c, which are the insertion destinations, respectively. The gap between the front ferrule 3 and the pipe 5 is filled with a soft front seal portion 3a and a back seal portion 4a, respectively. Since the front seal part 3a and the back seal part 4a are compressed by the metal joint body 1, the front ring part 3b, the back ring part 4b and the pipe 5 surrounding the periphery, sufficient confidentiality can be ensured.

  According to the present embodiment, since the contact portion of the front ferrule 3 and the back ferrule 4 with the tube 5 is formed of a softer material than the tube 5, the front ferrule 3 and the back ferrule 4 are pressed against the tube 5. Generation | occurrence | production of the thin part by damage and a deformation | transformation can be suppressed. Accordingly, it is possible to suppress a decrease in the earthquake resistance of the pipe 5. Moreover, when the material of the contact part with the pipe | tube 5 of the front ferrule 3 and the back ferrule 4 is resin, the effect which absorbs vibration with resin can also be anticipated. In addition, since it can be constructed by a simple procedure of simply tightening the nut 2 and pressing the front ferrule 3 and the back ferrule 4, it is possible to suppress an increase in the burden on the installer due to an increase in the construction procedure. Therefore, according to this Embodiment, the excessive deformation | transformation and damage of the pipe | tube 5 can be suppressed, and the fall of earthquake resistance can be suppressed, suppressing the increase in a construction procedure.

  Further, the pipe joint of the present embodiment is applicable to the pipe 5 of any material as long as the material of the front seal part 3a of the front ferrule 3 and the back seal part 4a of the back ferrule 4 is softer than the material of the pipe 5. be able to. In general, since the ferrule is made of metal, the material of the joint itself may be limited by the material of the pipe 5 due to a problem in strength. However, as in the present embodiment, for example, the front seal portion 3a of the front ferrule 3 is used. The back seal 4a of the back ferrule 4 is made of resin so that the material of the pipe 5 is not limited by the material of the pipe 5 as long as the target pipe 5 is made of metal. It is also a great merit that a common pipe joint can be used.

  Further, when the material of the front seal portion 3a of the front ferrule 3 and the back seal portion 4a of the back ferrule 4 is made of a fluororesin, the fluororesin is excellent in chemical resistance and heat resistance among the resins, and thus the pipe 5 is circulated. The allowable range of the type and temperature of the fluid to be used is wide, and it is possible to suppress the use range of the pipe joint from being narrowed by using the resin.

  Further, when all of the front ferrule 3 and the back ferrule 4 are made of resin, when the nut 2 is tightened, the ferrule may escape to the outside in the radial direction and there is a fear that the force for pressing the ferrule against the pipe 5 may be insufficient. . On the other hand, according to the present embodiment, only the front seal portion 3a and the back seal portion 4a that are in contact with the pipe 5 and the notches 1c, 3c of the front ferrule 3 and the back ferrule 4 are made of resin. Since the outer peripheral side of the front seal portion 3a and the back seal portion 4a is covered with the metal front ring portion 3b and the back ring portion 4b, the front seal portion 3a and the back seal portion 4a are secured when the nut 2 is tightened. Can be pressed against the tube 5 with sufficient force.

DESCRIPTION OF SYMBOLS 1 Joint body 2 Nut 3 Front ferrule 3a Front seal part 3b Front ring part 4 Back ferrule 4a Back seal part 4b Back ring part 5 Tube α Angle of front end of front ferrule with respect to outer peripheral surface of pipe β Notch of joint body Angle relative to the outer peripheral surface of the tube γ Angle of the tip of the back ferrule with respect to the outer peripheral surface of the tube δ Angle of the notched portion of the front ferrule with respect to the outer peripheral surface of the tube

Claims (6)

A joint body for inserting a metal pipe to be connected;
A nut fastened to the joint body through the tube;
A front ferrule that is interposed between the joint body and the nut and has a wedge-shaped tip portion pressed against the joint body by a fastening force of the nut;
A front ferrule interposed between the front ferrule and the nut and having a wedge-shaped tip portion pressed against the front ferrule by a fastening force of the nut;
A pipe joint characterized in that a contact portion of the front ferrule and the back ferrule with the pipe is formed of a softer material than the pipe.   2. The pipe joint according to claim 1, wherein the front ferrule includes a front seal part that contacts the pipe, and a metal front ring part that restrains the seal part together with the joint body and the pipe. Pipe fittings.   3. The pipe joint according to claim 2, wherein the back ferrule includes a back seal part that comes into contact with the pipe, and a back ring part that restrains the back seal part together with the front ring part and the pipe. Pipe fittings.   The pipe joint according to claim 3, wherein the front seal part and the back seal part are made of a fluororesin.   5. The pipe joint according to claim 4, wherein an angle of the front end portion of the front ferrule with respect to an outer peripheral surface of the pipe is in a state before the nut is fastened, of the notch portion of the joint body into which the front end portion enters. A pipe joint characterized by being smaller than an angle with respect to the outer peripheral surface.   5. The pipe joint according to claim 4, wherein, in a state before the nut is fastened, an angle of a tip portion of the back ferrule with respect to an outer peripheral surface of the tube is a notch portion of the front ferrule into which the tip portion enters. A pipe joint characterized by being smaller than an angle with respect to the outer peripheral surface.

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