JPH0680170U - High-pressure liquid supply pipe connection device for high-performance liquid chromatography - Google Patents

Abstract

(57) [Summary] [Purpose] A high-pressure liquid chromatography pipe connection device for high-performance liquid chromatography that can reliably make liquid-tight pipe connections and that can make liquid-tight pipe connections even after repeated disconnections and connections. To provide. A carbon fiber mixed PEEK resin ferrule 35 fitted to the high pressure liquid supply tube 25 and having frustoconical peripheral surfaces 57 and 58 at both ends is fitted to the high pressure liquid supply tube 25 and is attached to the tip side. Is screwed into the conduit member 30 to which the tube 25 is to be connected by a pressing screw member 36 made of a metal such as stainless steel having a truncated cone-shaped inner peripheral surface 70 to compressively deform the ferrule 25 in the axial direction, The frustoconical peripheral surfaces 57, 58 and the inner peripheral surface 60 of the ferrule 35 are connected in a liquid-tight manner.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention provides a high-pressure liquid chromatography pipeline for high-performance liquid chromatography, the pipeline having a high-pressure liquid-feeding pipeline portion, and a female screw portion formed on a peripheral wall near the open end of the pipeline portion. The present invention relates to a high-pressure liquid chromatography pipe connecting device for high-performance liquid chromatography for liquid-tightly connecting the high-pressure liquid pipe to the device. One end opening of the frustoconical inner peripheral surface of the conduit part of the conduit device having a high-pressure solution conduit part that constitutes a part of the high-pressure solution conduit. A ferrule configured such that the frusto-conical peripheral surface on the one end side is brought into liquid-tight contact with the pressurizing portion, which is fitted to the high-pressure liquid supply pipe and is brought into liquid-tight contact with the other end side of the ferrule. And a male screw part that is screwed into the female screw part of the conduit device, and the male screw part is the female screw part of the conduit device. For high-performance liquid chromatography having a pressing screw member configured to press the other end side of the ferrule when it is tightened into the ferrule to make the liquid-tight contact at both end sides of the ferrule. Related to the high-pressure liquid supply pipe connection device of.

[0002]

[Prior art]

 First, a typical high-pressure liquid-feeding pipe connecting device 101 of this type which has been conventionally used for high-performance liquid chromatography will be described with reference to FIGS. 10 and 11.

This high-pressure liquid-feeding pipe connection device 101 includes a high-pressure liquid-feeding pipe line portion 103 which constitutes a part of a high-pressure liquid-feeding pipe line 102 for high-performance liquid chromatography, and has an open end portion of the pipe line portion 103. A tube 107 serving as a high-pressure liquid supply pipe is liquid-tightly connected to a conduit device 106 (union made of stainless steel in the illustrated example) in which a female screw portion 105 is formed on a peripheral wall near 104.

This high-pressure liquid supply pipe connecting device 101 is a metallic ferrule 108 made of stainless steel or the like, which is a tubular body configured to be fitted in a metallic tube 107 made of stainless steel, and the ferrule 108. Similarly, a pressing screw member 109 made of metal such as stainless steel configured to be fitted in the tube 107 is provided. The ferrule 108 has a frusto-conical peripheral surface 111 formed on one end side 110, and the frusto-conical inner peripheral surface 112 of the one-end opening 104 of the high-pressure liquid supply conduit portion 103 of the union 106, which is a conduit device, has the conical-conical inner surface 112 on the one end side. The frusto-conical peripheral surface 111 of 110 is configured to be in liquid-tight contact. On the other hand, the pressing screw member 109 includes a pressing portion 114 that is in liquid-tight contact with the other end 113 side of the ferrule 108, a male screw portion 115 that is screwed to the female screw portion 105 of the union 106, and a device. And a hexagonal head portion 116 for forcibly screwing the male screw portion 115 to the female screw portion 105. When the male screw portion 115 is tightened into the female screw portion 105 of the union 106, the pressing portion 114 is The other end 113 side of the ferrule 108 is pressed to make the liquid tight contact with high pressure resistance on both sides 110, 113 of the ferrule 108.

However, in the case of the pipe connection device 101 of this type, in order to achieve the liquid-tight connection by the metal ferrule 108, it is necessary to forcefully screw the male screw portion 115 with the female screw portion 105. However, the metal ferrule 108 was actually inserted into the tube 107 and was actually fixed to the tube 107 with one tightening.

As a result, if the length A1 of the protruding portion 117 of the tube 107 is slightly longer than the length B1 of the cylindrical portion 118 at the back of the opening 104 of the union 106 to be used next, As shown in FIG. 11B, the peripheral surface 111 of the ferrule 108 cannot be brought into close contact with the frustoconical inner peripheral surface 112 of the union 106, so that sealing cannot be performed. On the contrary, if the length A2 of the protruding portion 117 of the tube 107 is slightly shorter than the length B2 of the cylindrical portion 118 at the back of the opening 104 of the union 106 to be used next, As shown in c), a gap 121 is formed between the tip 119 of the tube 107 and the bottom 120 of the cylindrical portion 118 of the union 106, and the flow of the liquid to be fed is disturbed in this portion, so that the liquid to be fed is If the sample to be analyzed is contained in the sample, it may not be possible to perform highly accurate chromatographic analysis. Even if the ferrule 108 can be moved with respect to the tube 107 after the fastening is released, the tube 107 and the ferrule 108 will still be deformed, so that the ferrule 108 will not be able to sufficiently seal the pipe when connecting it next time. I was afraid.

In such a case, in many cases, the tip side of the tube 107 is cut off together with the metal ferrule 108 fixed to the tip side of the tube 107, for example, at a portion indicated by reference numeral 121 in FIG. The metal ferrule 108 was attached, and the remaining tube 107 and the pressing screw member 109 were to be reused. However, when the cut surface 122 of the tube 107 is not accurately formed or the cut surface 122 is not precisely finished, for example, a gap 123 as shown in FIG. There is a possibility that a problem similar to the case of (1) may occur. Further, the screw member 109 may be broken or broken due to metal fatigue.

On the other hand, in order to avoid such a problem due to the ferrule being made of metal, a PEEK resin ferrule (or ferrule) 130 and a knurled handwheel 131 are provided as shown in FIG. A pipe connecting device 133 including a pressing screw member 132 is also known. In the pipe connecting device 133, the same elements as those of the pipe connecting device 101 shown in FIGS. 10 and 11 are designated by the same reference numerals.

However, in the case of this pipe connection device 133, the ferrule 130 remains in the opening 104 of the pipe line device 106 and cannot be taken out, or the ferrule 130 has a cylindrical shape due to the high pressure of the liquid in the pipe line 102. The outer peripheral surface 135 of the tube 107 may slip with respect to the peripheral surface 134 and the tube 107 may come off.

Further, in order to avoid the above problem of the pipe connecting device 101 of FIGS. 10 and 11 due to the ferrule being made of metal, a ferrule (or ferrule) 150 made of polyimide resin as shown in FIG. 13 is used. Also known is a pipe connecting device 153 including a pressure screw member 152 made of PPS (Polyphenylene Sulfit) having a hand-wound portion 151. In the case of this connecting device 153, the tubular ferrule 150 has frustoconical peripheral surfaces 154 and 155 on both ends 110 and 113 sides, and the peripheral surfaces 154 and 155 correspond to the opening of the union 106. The conduit 102 is configured to be sealed by closely contacting the truncated cone-shaped inner peripheral surface 112 of 104 and the truncated cone-shaped inner peripheral surface 156 of the pressing portion 114 of the pressing screw member 152. In the pipe connecting device 153, the same elements as those of the pipe connecting device 101 of FIGS. 10 and 11 are designated by the same reference numerals.

However, also in the case of this pipe connection device 153, the male screw portion 115 of the resin pressure screw member 152 is deformed, the tightening force stress of the ferrule 150 becomes weak, and the liquid in the pipe line 102 is Due to the high pressure, the outer peripheral surface 158 of the tube 107 may slip with respect to the cylindrical inner peripheral surface 157 of the ferrule 150, and the tube 107 may come off.

[0012]

[Problems to be solved by the device]

 The present invention has been made in view of the above points, and an object of the present invention is to reliably perform liquid-tight pipe connection and to perform liquid-tight pipe connection even if disconnection / connection is repeated many times. It is to provide a high-pressure liquid-feeding pipe connecting device for high-performance liquid chromatography that can be performed.

[0013]

[Means for Solving the Problems]

 According to the present invention, the above-mentioned object is that the ferrule has frusto-conical peripheral surfaces on both ends thereof, and one end of the frusto-conical inner peripheral surface of the high-pressure liquid feeding conduit portion of the conduit device has one end of the ferrule at the opening. Side frustum-shaped inner peripheral surface is configured to be liquid-tightly contacted, and the pressing screw member is fluid-tightly contacted to the frustum-shaped conical surface on the other end side of the ferrule. The pressing screw member is made of a metal having the same rigidity as that of the high-pressure liquid feeding conduit portion of the conduit device, and the ferrule is a resin having a rigidity lower than that of the metal. This is achieved by a high-pressure liquid-feeding pipe connecting device for high-performance liquid chromatography, which is characterized by comprising a system material.

[0014]

In the pipe connecting device of the present invention, since the ferrule is made of a resin material having a lower rigidity than the metal that constitutes the pressing screw member and the high pressure liquid feeding conduit portion of the conduit device, the ferrule is simply pressed. By simply tightening the male thread portion of the screw member into the female thread portion of the conduit device, the pressing portion of the conical trapezoidal inner circumferential surface of the pressing screw member pushes the frustoconical circumferential surface of the ferrule on the other end side. , The ferrule may be deformed so that the liquid-tight abutment on the frusto-conical peripheral surfaces on both ends of the ferrule can be performed.

Moreover, in the pipe connecting device of the present invention, a resin having a rigidity lower than that of the metal (or a resin having a rigidity similar to that of the metal) forming the pressing screw member and the high-pressure liquid supply conduit portion of the conduit device. A ferrule made of a system material is provided with frusto-conical peripheral surfaces on both ends thereof, and the ferrules are pressed by the conical frusto-conical peripheral surfaces to abut on the conical frusto-conical inner peripheral surface of the screw member and the high-pressure liquid feeding conduit portion of the conduit device. The male ferrule of the pressing screw member is only tightened to the female screw of the conduit device, and the ferrule is not only deformed in the axial direction but also in the radial direction without actually deforming the pipe. Since it is compressed and deformed, the inner peripheral surface of the ferrule is strongly pressed against the outer peripheral surface of the pipe in which the ferrule is fitted, and the seal between the inner peripheral surface of the ferrule and the outer peripheral surface of the pipe in which the ferrule is fitted. Not only can it be done reliably, A large frictional force may be applied between the base and the pipe, and there is less risk of the pipe slipping axially with respect to the ferrule. Also, if the ferrule and the conduit device are unscrewed, the ferrule can return to almost its original state.Therefore, when the pipes are connected again, it is only necessary to advance the screwing of the pressing screw and the conduit device, It can be moved longitudinally with respect to the pipe to ensure the desired sealing. Therefore, there is practically no risk of leaving excessive space in the pipe connection. Further, since the ferrule is deformed at the time of this sealing, even if the shape, size, etc. of the high-pressure liquid feeding conduit portion of the conduit device differ to some extent, this difference can be compensated for sealing. Since the ferrule is made of a resin material having a rigidity lower than that of the metal (or a resin having the same rigidity as the resin) that constitutes the high-pressure liquid-feeding conduit part of the pressure screw member and the conduit device, the high-pressure liquid-feeding Since there is no possibility that excessive force will be applied to the pipe having the possible strength, a resin pipe may be used as the pipe material. Also, if the ferrule is greatly deformed due to repeated use over a long period of time or its sealing performance deteriorates, only this ferrule should be removed from the pipe and replaced. Therefore, the pipe length between the pipe line devices can always be kept constant, and the pipe length can be minimized, so that the analysis accuracy and sensitivity can be kept high.

[0016]

[Preferable Embodiments of Problem Solving Means]

 The diameter of the maximum outer diameter portion of the ferrule when the male screw portion of the pressing screw member is fastened to the female screw portion of the conduit member is preferably the maximum outer diameter portion of the frustoconical inner peripheral surface of the pressing screw member. Larger than the diameter of. In this case, a large compressive stress is applied to the ferrule at the contact portion between the end wall portion that defines the maximum outer diameter portion of the conical trapezoidal inner peripheral surface of the pressing screw member and the conical trapezoidal peripheral surface of the ferrule. The close contact of the frusto-conical surface of the ferrule with the adjacent member is ensured in this part. Further, even if the ferrule made of resin is plastically deformed by repeated use under high stress, the above-mentioned portion is brought into close contact, so that it can be used many times.

The ferrule is preferably made of PEEK (polyether ether ketone) resin mixed with carbon fiber. As will be described later, it has been confirmed by a large number of practical tests described later that a pipe connecting device equipped with a PEEK resin ferrule mixed with carbon fiber can reliably achieve a liquid-tight pipe connection for a long period of time. The ferrule is preferably formed by injection molding. The temperature at the time of this injection molding is about 380 to 400 ° C.

The apex angle of the cone forming the frustoconical peripheral surface of the ferrule is preferably smaller than the apex angle of the cone forming the frustoconical inner peripheral surface of the pressing portion of the pressing screw member. . In this case, when the male screw portion of the pressing screw member is tightened into the female screw portion of the conduit device, the ferrule is compressed and deformed in the axial direction, and the conical surface of the ferrule and the circular truncated cone shape of the pressing screw member are It will be in close contact with the surrounding surface.

When the apex angle of the cone forming the frustoconical inner peripheral surface of the pressing portion of the pressing screw member is about 40 degrees, the cone forming the frustoconical peripheral surface of the ferrule is The apex angle is preferably about 27 degrees. If the apex angle is too large or too small, it may be difficult to perform stable sealing for a long time (many times).

The apex angle of the cone forming the frustoconical inner peripheral surface of the pressing portion of the pressing screw member is substantially equal to the apex angle of the frustoconical inner peripheral surface of the conduit portion of the conduit member, and is preferably Is 38 to 42 degrees. This allows the ferrules to be bilaterally symmetric so that the apex angles of the two frustoconical surfaces of the ferrule are the same.

[0021]

【Example】

 Next, a preferred embodiment of a high-pressure liquid chromatography high-pressure liquid supply pipe connecting apparatus 1 according to the present invention will be described with reference to FIGS. 1 to 9.

Before describing the details of the pipe connection device 1, first, an outline of a high performance liquid chromatography (hereinafter, referred to as “HPLC”) device 2 to which the pipe connection device 1 is applied will be described.

In FIG. 2, when the eluent 4 in the liquid reservoir 3 is being sent by the high-pressure pump 5 to the thin liquid delivery conduit 6, the sample to be analyzed is piped by the manual sample injector 7 or the automatic sample injector 8. The type and amount of the components in the sample are detected by a detector 10 such as an ultraviolet detector and a data processing device 11 connected to the detector 10, such as an ultraviolet detector, after being injected into a channel 6 and separated in a column 9. In addition, 12 is a suction filter, 13 is a degasser, 14 is a purge valve, 15 is a line filter, 16 is a trap, 17 is a temperature control device, 18 is an additional detector such as a refractive index detector, 19 is a recorder, 20 is a liquid discharge pipe. When plural kinds of eluents are used, for example, when three kinds of eluents are used, the respective devices are arranged in parallel as shown with subscripts a and b, respectively, and the gradient control device 21, which controls the respective feeding ratios, 21a, 21b are provided. Further, the discharge side pipes 22, 22a, 22b of the high-pressure pump are connected via a four-way joint 23 to a tube 24 leading to a line filter 15 connected to the sample injectors 7, 8.

By the way, in the case of HPLC, the pressure is several tens to several hundreds of atmospheric pressures on the discharge side of the pumps 5, 5a, 5b, that is, on the high-pressure side. Therefore, the tube 25 as the high-pressure side pipe (typically its outer diameter is about 1.59 mm, its inner diameter is 0.1 to 1.0 mm, typically 0.25 to 0.8 mm) At the connection part 26 between the equipment 5 and 5a, 5b, 23, 15, 7, 7, 8, 9 and 16 as a conduit device, a liquid-tight pipe connection device capable of withstanding high pressure is required. The pipe connection device 1 is disposed in the.

On the other hand, the tubes 5, 5a, 5b, 23, 15, 7, 8, 9, and 16 which are the main conduit devices are not directly connected to each other by the tube 25. Since it is possible to provide a union 27 or the like (of course, the four-way joint 23 may be regarded as a kind of the connecting device here) which is a connecting device of the above, an example using a large number of unions 27 is shown here. From the viewpoint of improving analysis accuracy and sensitivity, it is desirable to minimize the arrangement of the union 27. When the pipe connecting device 1 is used, the union 27 may be omitted. It can also be unused. The connecting portion 28 between the tube 25 and the connecting tool such as the union 27 also needs a liquid-tight pipe connecting device capable of withstanding high pressure, and the pipe connecting device 1 is arranged in this connecting portion 28. In the illustrated example, one tube 25 is directly connected between the pump 5 and the four-way joint 23, but a union 27 and the like may be provided here as well. Moreover, if there is practically no possibility of accumulating or disturbing the flow of the liquid passing through the pipeline 6, if desired, two or more unions or the like may be directly connected between adjacent main pipeline devices via piping. May be connected in columns.

Since the pipe connection portion of the pipeline device has substantially the same structure and shape in practice, hereinafter, the pipeline device is generically denoted by reference numeral 30 unless otherwise specified.

Next, the configuration of the pipe connecting device 1 will be described in detail with reference to FIGS. 1 and 3 to 5. FIG. 1 is a cross-sectional explanatory view showing a state in which the tube 25 is connected to the conduit device 30 by the pipe connecting device 1, and the pipe connecting device 1 comprises a ferrule 35 and a pressing screw 36. 3 is a cross-sectional explanatory view of the ferrule 35 of the pipe connecting device 1 when no external force is applied to the ferrule 35, FIG. 4 is a cross-sectional explanatory diagram of the pressing screw 36 of the pipe connecting device 1, and FIG. FIG. 3 is a cross-sectional explanatory view of a union 27 as an example of FIG.

The conduit device 30 is provided at its central portion with a high-pressure liquid supply conduit part 41 that constitutes a part of the high-pressure liquid supply conduit 6 of the HPLC apparatus 2. The pipe line portion 41 of the pipe line device 30 is made of metal such as stainless steel (for example, SUS316) or a resin that is chemically stable with the same degree of rigidity, and has a pore 42 similar to the tube 25 at the axial center. And a cylindrical hole portion 45 into which the tip end portion 44 of the tube 25 to be connected is to be inserted is provided at a position closer to the opening 43 than the fine hole, on the side of the opening 43 of the cylindrical hole portion. A frustoconical hole portion 46 for receiving one end side of the ferrule 35 is provided, and a cylindrical screw hole portion 48 in which a female screw 47 is cut is provided at the opening end side of the opening 43. A screw-free cylindrical hole 49 is provided between the screw hole 48 and the truncated cone-shaped hole 46.

In the case of FIG. 5, since the conduit device 30 is the union 27, the other end opening 50 side in the axial direction of the high-pressure liquid supply conduit part 41 is also provided with hole portions 45, 46, 49 similar to the opening 43 side. , 48 etc. are formed.

Returning to the description of the pipe connection device 1 itself, as shown in FIG. 3, the ferrule 35 is tapered toward both ends 55, 56 toward the ends 55, 56 when no external force is applied. It has a circular truncated cone-shaped peripheral surface 57, 58, and a cylindrical peripheral surface 59 between the peripheral surfaces 57, 58.

In the state shown in FIG. 3, the ferrule 35 can slide on the tube 25 in the axial direction, and the inner diameter C of the ferrule 35 is almost equal to the outer diameter of the tube 25 (1.59 mm = 1/16 inch). equal. For example, the inner diameter C, the maximum outer diameter D, the minimum outer diameter E, and the length F of the ferrule 35 are, for example, 1.6 mm, 3 mm, 2 mm, and 5.5 mm, respectively. For E, +0.05 mm, ± 0. It is about 05 mm and ± 0.05 mm, and the length F is about ± 0.1 mm. The apex angle G 1 of the cone forming the frustoconical peripheral surfaces 57 and 58 of the ferrule 35 is about 27 to 30 degrees, and in this example, it is 27 degrees. The apex angles G of the two surfaces 57, 58 may be different.

In the case of this example, although the cylindrical peripheral surface 59 is formed over a considerable length, the ferrule undergoes plastic deformation such that the axial length of the ferrule is shortened by repeated use as described later. If the ferrule 35 has a relative length that allows the ferrule 35 to project from the open end 43 of the conduit device 30 and be picked up even after the ferrule 35 has been received by the pipe 35, the peripheral surface portion 59 may be omitted.

The ferrule 35 is formed by injection molding PEEK resin mixed with carbon fiber at a temperature of about 380 to 400 degrees. Although this ferrule material has lower rigidity and is more easily deformed than metals such as stainless steel, which is the material of the pressing screw member, it has a seal withstand pressure capable of performing sealing under a pressure of about 100 kg / cm ^{2 in} HPLC. , It should have much higher rigidity than ordinary rubber. Further, it is preferable that the ferrule material has such a tenacity that it is plastically deformed without causing cracks or the like under the action of a force exceeding the elastic limit. It is natural that the ferrule material should have chemical stability with respect to the liquid for HPLC for the purpose of its use, but it is preferable that the ferrule material is not fixed to the metal even under pressure. Practically, it is preferable to use one that is easy to process and inexpensive.

The material of the ferrule 35 may be, for example, pure PEEK instead of PEEK (polyetheretherketone) resin mixed with carbon fiber. Other resin materials may be used as long as they have the same physical properties as the carbon fiber mixed PEEK resin and the like from the above viewpoint.

Notches 61, 61 are formed in the peripheral walls at both ends of the through hole 60 of the ferrule 35. The notch 61 is provided to prevent breaking and debris in order to facilitate die-cutting, and in the example of FIG. 3, it is, for example, about 0.5 mm, but in some cases, it may be omitted. Good.

The pressing screw member 36 of the pipe connection device 1 is made of metal such as stainless steel having rigidity and chemical stability, and as shown in an enlarged view of FIG. When the outer circumference of the tubular body is focused, the tubular body has a large-diameter base side cylindrical portion 65, a small-diameter tip side cylindrical portion 66, and both cylindrical portions 65, It consists of three parts, an intermediate diameter cylindrical part 67 located between 66.

The cylindrical portion 67 is a male screw portion in which a male screw 68 is cut on the outer circumference. The large-diameter cylindrical portion 65 is a portion for applying a force by pinching the push screw 36 when it is turned by hand, and is roughened such as knurling and grooves 69 on the outer circumference.

On the other hand, the end portion on the small diameter portion 66 side is expanded in a truncated cone shape, and the truncated cone-shaped inner peripheral surface 70 functions as a pressing surface of the pressing portion 71 against the ferrule 35. More specifically, the truncated cone-shaped peripheral surface 70 extends from the small diameter portion 66 to a part of the male screw portion 67 via a transition portion 72 between the small diameter portion 66 and the male screw portion 67. The surface 70 is subjected to surface processing so as to reduce the surface roughness as much as possible. The apex angle H of the cone forming the frustoconical inner circumferential surface 70 of the pressing portion 71 forms the frustoconical circumferential surfaces 57, 58 of the ferrule 35 when the ferrule 35 is in the unpressed state, that is, in the non-compressed state. When the apex angle G is larger than the apex angle G of the cone, which is about 27 degrees as described above, it is about 40 degrees, for example. The apex angle H is the same as or about the same as the apex angle of the cone forming the truncated cone-shaped peripheral surface (hole) 46 of the conduit member 30.

The maximum diameter portion J of the truncated conical surface 70, that is, the inner diameter J of the tip 73 of the small diameter portion 66 is larger than the outer diameter D of the uncompressed ferrule 35, for example, 3.2 mm ± 0. ． It is 1 mm. On the other hand, the outer diameter K of the small-diameter portion 66 is 3.6 mm ± 0. It is 1 mm. The frusto-conical peripheral surface portion 70 has a depth L of, for example, about 1 mm, and the transition portion 66 has a length M of, for example, about 0.7 mm. The small diameter portion 66 may have a larger diameter as long as the tip 73 side of the pressing screw member 36 can enter the opening 43 of the conduit member 30 while the ferrule 35 is being pressed. In some cases, it may not be necessary as long as it does not interfere with.

Next, the connection of the tube 25 to the conduit device 30 by the pipe connecting device 1 having the above structure will be described in more detail with reference to FIGS. 1, 3 and 4.

First, the screw member 36 and the ferrule 35 are press-fitted on the tip end 44 side of the tube 25, and the end surface 75 of the tip end 44 of the tube 25 is attached to the bottom wall of the cylindrical hole 45 of the conduit member 30. Push in until it touches 76. At this time, the ferrule 35 is inserted until the radially inner portion of the frustoconical peripheral surface 57 on the distal end side abuts the corresponding radial portion of the frustoconical peripheral surface 46 of the conduit member 30. Next, the male screw portion 67 of the pressing screw member 36 is screwed into the female screw portion 47 of the conduit member 30 by manually rotating the manual screwing portion 65 of the pressing screw member 36. When the pressing screw member 36 is further screwed, the radially inner portion of the frustoconical inner peripheral surface 70 of the pressing portion 71 of the pressing screw member 36 corresponds to the corresponding radial portion of the frustoconical peripheral surface 58 on the front side of the ferrule 35. And further presses and compresses the circular truncated cone-shaped peripheral surface 58 in the axial direction N. Along with this axial compressive deformation, the wider portions of the frustum-cone-shaped peripheral surfaces 57 and 58 of the ferrule 35 form the frustum-shaped peripheral surface 46 of the conduit member 30 and the frustum-shaped conical portion of the pressing portion 71 of the pressing screw member 36. The inner peripheral surface 70 comes into close contact with the corresponding diametrical portion (the close range increases depending on the degree of plastic deformation due to the use of the ferrule 35), and the ferrule 35 includes the conduit member 30 and the pressing screw portion. A portion of the material 36 axially distant from the frustoconical peripheral surfaces 46, 70, that is, a portion 77 defined by a substantially cylindrical peripheral surface 59, expands radially outward P. Therefore, the cylindrical peripheral surface 59 of the ferrule 35 originally located at the position indicated by the broken line P1 comes to the position indicated by the solid line P2 in FIG. 1, for example. As a result, the frustoconical peripheral surfaces 57, 58 of the ferrule 35 (mainly at least a part of the inner side in the radial direction) are in close contact with (the corresponding radial portions of) the frustoconical inner peripheral surfaces 46, 70 of the adjacent members 30, 36. In addition to being clamped, the bases 77a and 77b of the radially outwardly projecting portion 77 are strongly and closely attached to the corner portion 79 of the duct member 30 and the tip portion 66a of the small diameter portion 66 of the pressing screw member 36 which are adjacent to each other. And perform high pressure resistant sealing. Even at this time, normally, as shown in FIG. 1, a part 47a of the female screw portion 47 remains without being screwed into the male screw portion 67.

On the other hand, along with the movement of the frustoconical inner peripheral surface 70 of the pressing portion 71 in the N direction, the frustoconical peripheral surfaces 46 and 70 of the conduit member 30 and the pressing screw member 36 of the ferrule 35 are moved. The portion 78 defined by the portion in direct contact is also pressed inward in the radial direction Q. Therefore, the cylindrical inner peripheral surface 60 of the ferrule 35 is strongly brought into close contact with the outer peripheral surface 80 of the tube 25 to perform a high-pressure-proof seal and prevent the tube 25 from slipping and slipping out of the ferrule 35 in the axial direction N1.

Since there is a slight gap 81 between the inner peripheral surface 64 of the screw portion 67 of the pressing screw member 36 and the outer peripheral surface 80 of the tube 25, as shown by reference numeral 82, the ferrule also exists in this gap 81. The material of 35 deforms and enters, and the sealing property of the ferrule 35 is enhanced, and the performance of preventing the tube 25 from slipping and coming off is enhanced. For the same reason, the tip of the ferrule 35 is also slightly pushed between the tube 25 and the hole 45 (1.6 + 0.05 mm) of the conduit device 30.

By the way, since carbon fiber mixed PEEK, which is a material of the ferrule 35, undergoes plastic flow deformation to some extent as a resin under a high pressure, when the ferrule 35 is repeatedly used, the shape of the ferrule 35 in a state in which the external force is removed is It changes gradually and becomes shorter in the axial direction N until the material portion 77 comes into close contact over a considerable range of the circumferential surface of the cylindrical hole 49 of the conduit member 30 as shown by the broken line 77c. The material portion 82 spreads outwardly and penetrates into the gap 81 for a long time.

As described above, even if the axial length of the ferrule 35 changes, the male screw portion 67 of the pressing screw member 36 is deeply screwed into the female screw portion 47 of the conduit member 30 to allow the ferrule 35 to move. The function can be kept practically the same for a long time. The outer diameter of the hand-turning portion is selected so that the degree of this screw-in corresponds to the point where the force required to pinch and turn the hand-turning portion 65 sharply increases.

It should be noted that the position of the tube 25 is displaced due to a momentary increase in hydraulic pressure caused by opening and closing of a valve during the operation of the HPLC device 2, and the end surface 75 of the tube 25 and the high-pressure liquid feeding conduit of the conduit device 30 are displaced. If a gap is formed between the hole 45 of the portion 41 and the bottom surface 76, or if liquid leakage occurs due to plastic deformation of the ferrule 35 due to long-term use under high pressure, for example, the recorder 19 These problems can be seen due to abnormal output waveforms, etc., so once the screwing part is loosened and the position of the tube 25 is adjusted, the screwing part is retightened, or the screwing part is simply tightened again. Even in the case, the HPLC apparatus 2 can be easily and surely returned to the original operating state by simply replacing the ferrule 35.

Next, a description will be given of a test performed on changes in sealing performance when the pipe connecting device is repeatedly used.

[0048]

[Actual test]

 From the three test bodies 1, 2 and 3 including the pipe connecting device 1 of the embodiment of the present invention, the comparative test body 1 including the conventional pipe connecting device 133 of FIG. 12 and the conventional pipe connecting device 153 of FIG. The comparative test body 2 was tested for durability performance in terms of sealing function and the like.

The test assumes the use of the pipe connecting device at a place where the frequency of opening and closing of the pipe, that is, the frequency of connecting and disconnecting the pipe connecting device is high, and connecting the pipe connecting device and pressurizing / depressurizing the pipe. The three steps from disconnection of the pipe connection device were repeated, and how the sealing performance changed depending on the number of repetitions was examined by changing the maximum pressure resistance. More specifically, each time, the change in withstand pressure with the increase in the number of repetitions, the change in the shape of ferrules, the presence or absence of liquid leakage, and the presence or absence of slip between the pipe and the connecting device were examined.

In the test, as shown in FIG. 6, the discharge side of the high-pressure pump 5 as a conduit device was connected to the back pressure pipe 85 and the pressure gauge 86 via the test body and the tube 25. Next, the pump 5 was pressurized to 350 kg / cm ² , the pump 5 was stopped, and the reading with the pressure gauge 86 after 2 minutes was recorded. Even if liquid leaks during pressurization, the pressure is forcibly increased until the pressure reaches 350 kg / cm ² without changing the connection state of the pipe connection device (without changing the screwing state of the pressing screw member). did. When the seal performance deteriorated and the pressure could not be increased to 350 kg / cm ² , the maximum pressure that could be increased was recorded.

Further, every time the pressure was measured and then returned to atmospheric pressure, the connection by the pipe connecting device 1, 133 or 153, which is a test body or a comparative test body, was released, and the ferrule portion and the like were taken out and observed. In this observation, the length S (see FIG. 9) from the curved portion 35a near the tip of the ferrule 35, 130 or 150 to the tip 75 of the tube 25 is measured to check for slip, and the ferrule 35, 130, or 150 changes in shape were observed and recorded.

The test results are shown in FIGS. 7 to 9 and Tables 1 and 2.

First, the change in breakdown voltage will be described. 7 (a) and 7 (b) show the average value of the pressure 2 minutes after the pump was stopped every 20 times (for example, in the case of the test body 1, 348 at 40 is the test body). 1, the average value of the 20th withstand voltage from the 21st time to the 40th time was 348kg / cm. ² It was that). Further, in FIG. 7A, the polygonal lines 87a, 87b, 87c and the polygonal lines 88a, 88b show the results for the test bodies 1, 2, 3 and the comparative test bodies 1, 2, respectively.

As can be seen from FIG. 7, in the case of the test bodies 1 to 3, the pressure was practically increased to the maximum value up to about 120 to 140 times, whereas in the case of the comparative test body 1, the pressure was increased up to about 40 times. The withstand voltage dropped sharply, and even in the case of the comparative test body 2, the withstand voltage was visibly lowered after about 60 times.

More specifically, in Test bodies 1 to 3, the pressure could be increased up to 350 kg / cm ² up to 120 times without liquid leakage. In the test body 3, liquid leakage occurred at the 131st time, the pressure after 2 minutes dropped to 321 kg / cm ² , and at the 139th time, the pressure after 2 minutes dropped to 230 kg / cm ² . However, in the test body 3, the sealing performance was restored again after the 132nd time and the 140th time, and the pressures after 2 minutes at the 132th time and the 140th time were 346 kg / cm ² and 348 kg / cm ² , respectively. .

8 (a) and 8 (b), regarding the test bodies 1 to 3, the minimum value of the pressure at the time of 2 minutes after the pump was stopped every 5 times after the 140th time (for example, the test body 1). 340 at 140 indicates that in test body 1, the minimum value of the withstand voltage of 5 times from the 140th time to the 144th time was 342 kg / cm ² ) and the broken lines 87a, 87b. , 87c. As is clear from a comparison of FIG. 8 with FIG. 7, in the case of the test bodies 1 to 3, there is no data that significantly deviates from the average value. In other words, it can be seen that there is practically no risk of unexpected pressure drop.

Next, regarding the liquid leakage, in all of the test bodies 1 to 3, there was no liquid leakage up to the 120th time, and among the test bodies 1 to 3, the test body 3 was tested at the 131st and 139th time. Although there was a liquid leak, the liquid leak actually disappeared at the 140th time. The liquid leakage gradually started from the 160th time. On the other hand, in the comparative test body 1, liquid leakage occurred at the 43rd time and was once recovered at the 44th time, but the liquid leakage gradually became severe after the 45th time, and at the 75th time, sealing became impossible. Further, in the case of the comparative test body 2, liquid leakage occurred at the 60th time, and the pressure dropped twice. After that, the liquid leakage gradually became more severe, and after the 75th to 100th times, the liquid leakage was remarkable and the level at which the pressure could be increased significantly decreased.

As for the slip between the pipe and the connecting device, in the test bodies 1 to 3, practically no slip occurred until the 140th time when practically no problems occurred in the pressure resistance and the liquid leakage. In the comparative test body 1, some slip occurred early. On the other hand, in the comparative test body 2, although it seemed that there was no problem on the pressure resistance data, in fact, a clear slip occurred 4 times by the 43rd time.

Further, regarding the change in shape of the ferrule, in the case of the test bodies 1 to 3, the plastic deformation as detailed in the description of FIG. After about 160 times, the shape gradually became as shown in FIG. 9 and the sealing property was lost. However, the shape change was gradual. In the case of the comparative test body 1, the shape change was small, and the tip portion was mainly deformed. In the case of the comparative test body 2, the shape change was almost the same as that of the test bodies 1 to 3, but since the material was less tenacious, cracks, tears and cracks were formed at both ends and the maximum diameter part. This is considered to be the cause of liquid leakage and inability to seal.

In the case of the comparative test body 1, if the ferrule remained in the opening 104 of the conduit device 106 when the screwed state was released, it was practically impossible to take out the ferrule due to its shape.

The summary of the sealing performance and the change in shape due to the above deterioration is summarized in Table 1 below.

[0062]

[Table 1]

According to the above-mentioned test results, the test piece which is the pipe connection device 1 of the preferred embodiment according to the present invention is much better than the comparative test pieces 1 and 2 and is stable. You can see that In the pipe connection device 1, the ferrule 35 gradually deforms toward the gap around the seal portion due to the accumulation of stress, but since it is manually turned, there is little possibility that the tightening torque of the screw portion becomes excessive. Occurs only gradually. Although it is considered that the service life will vary slightly depending on the usage conditions, individual differences of users, etc., the inventor of the present invention has no problem when using it as a normal HPLC piping connection device. I think that it will only be the variation of. On the other hand, the comparative test body 1 is less durable because the tip of the ferrule is easily worn. Further, in the comparative test body 2, slip is likely to occur, and there is a risk that the pipe may actually come off, and it will be necessary to interrupt or redo the HPLC analysis, and in practice it is difficult to use with confidence. This easiness of slippage is considered to be due to a bad combination of materials for the ferrule and the push screw member in terms of rigidity and the like.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a pipe connecting device according to a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram of an HPLC device to which the pipe connecting device of FIG. 1 is applied.

FIG. 3 is an explanatory cross-sectional view of a ferrule of the device of FIG.

4 is a cross-sectional explanatory view of a pressing screw member of the apparatus of FIG.

5 is a cross-sectional explanatory view of the union of the HPLC apparatus of FIG. 2, which is an example of a pipe line apparatus connected to a pipe by the connecting apparatus of FIG. 1.

FIG. 6 is an explanatory diagram of a test device.

FIG. 7 is a diagram showing a measurement result of deterioration due to fatigue in a test.

FIG. 8 is a diagram showing the results of measuring the minimum withstand voltage value five times in each test.

FIG. 9 is an explanatory diagram showing a deformed state of the ferrule at the final stage of the test.

FIG. 10 is an exploded perspective view of a conventional ordinary pipe connecting device.

FIG. 11 is an explanatory cross-sectional view of the connecting device of FIG. 10 in various usage states.

FIG. 12 is an explanatory cross-sectional view of another conventional pipe connection device.

FIG. 13 is an explanatory cross-sectional view of still another conventional pipe connection device.

[Explanation of symbols]

 1 Pipe Connection Device 2 HPLC Device 5 Pump (Pipe Line Device) 7 Manual Sample Injector (Pipe Line Device) 8 Automatic Sample Injector (Pipe Line Device) 9 Column (Pipe Line Device) 15 Line Filter (Pipe Line Device) 16 Trap (pipe line device) 23 Four-way joint (pipe line device) 27 Union (pipe line device) 30 Pipe line device 35 Ferrule 36 Pressure screw member 41 High pressure liquid feeding pipe line portion 43 Opening 46 Frustum of conical hole (inner peripheral surface) ) 47 female screw portion 57 frustoconical peripheral surface 58 frustoconical peripheral surface 67 male screw portion 70 frustoconical peripheral surface 71 pressing portion

Claims (5)

[Scope of utility model registration request] 1. A tube comprising a high-pressure liquid-feeding conduit portion which constitutes a part of a high-pressure liquid-feeding conduit for high-performance liquid chromatography, and a female screw portion formed on a peripheral wall near the open end of the conduit portion. A high-pressure liquid chromatography connecting device for high-performance liquid chromatography for liquid-tightly connecting a high-pressure liquid sending pipe to a channel device,
It is composed of a tubular body having a truncated cone-shaped peripheral surface formed on both end sides and configured to be fitted into the high-pressure liquid-feeding pipe, and is provided with a high-pressure liquid-feeding conduit portion that constitutes a part of the high-pressure liquid-feeding conduit. A ferrule configured such that the frustoconical peripheral surface on one end side is brought into liquid-tight contact with one end opening of the frustoconical inner peripheral surface of the duct portion of the duct device, and the ferrule is fitted to the high-pressure liquid delivery pipe. And a male screw portion screwed to a female screw portion of the conduit device and a pressing portion of the inner peripheral surface of the circular truncated cone that is liquid-tightly contacted with the circular truncated cone peripheral surface on the other end side of the ferrule. When the male threaded portion is tightened into the female threaded portion of the conduit device, the pressing portion of the frustoconical inner circumferential surface pushes the frustoconical circumferential surface on the other end side of the ferrule, and the cones on both end sides of the ferrule. A pressing screw member configured to make the liquid-tight abutment on the trapezoidal peripheral surface, the pressing screw member being a high pressure of the conduit device. A high-pressure liquid chromatography connection device for high-performance liquid chromatography, characterized in that the ferrule is made of a metal having the same degree of rigidity as that of the liquid feed pipe portion, and the ferrule is made of a resin material having a lower rigidity than the metal. 2. The diameter of the maximum outer diameter portion of the ferrule when the male screw portion of the pressing screw member is tightened in the female screw portion of the conduit member is the maximum outer diameter portion of the frustoconical inner peripheral surface of the pressing screw member. The pipe connection device according to claim 1, wherein the pipe connection device has a diameter larger than the diameter. 3. The pipe connecting device according to claim 1, wherein the ferrule is made of PEEK (polyetheretherketone) resin mixed with carbon fiber. 4. The apex angle of the cone forming the frustoconical peripheral surface of the ferrule is smaller than the apex angle of the cone forming the frustoconical inner peripheral surface of the pressing portion of the pressing screw. The pipe connection device according to any one of items 1 to 3. 5. The pipe connecting device according to claim 1, wherein the apex angle of the cone forming the frustoconical peripheral surface of the ferrule is 27 degrees.