JP3254228B2 - How to connect sanitary piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting a sanitary piping system for a production device for pharmaceuticals, foods, etc., and more particularly, to a specific sanitary piping integrally formed of porous polytetrafluoroethylene. The present invention relates to a method of arranging gaskets for tightly connecting sanitary piping systems.

[0002]

2. Description of the Related Art Sanitary pipe gaskets used in manufacturing equipment for pharmaceuticals, foods, etc., are designed to prevent impurities from eluting into products from the material forming them.
The materials were carefully selected, and many were made of silicon-based plastics. In the manufacture of the above pharmaceuticals,
Since it is necessary to perform product management particularly strictly, the frequency of device cleaning is extremely high as compared with other manufacturing devices. In these devices, particularly in the production of pharmaceuticals, alkali cleaning or cleaning with alkali and saturated steam is often performed in order to remove pyrogen, which is a so-called pyrogen for the living body. However, conventionally used silicon-based plastics have poor alkali resistance, and may have various adverse effects after cleaning. For example, even when an alkali component slightly remains on the gasket surface, when the apparatus is steam-sterilized, there is a disadvantage that the gasket adheres to the flange metal surface.

On the other hand, in order to solve the above-mentioned drawbacks of the silicone plastic gasket and to use it in various devices, packing, gaskets, O-rings and the like made of polytetrafluoroethylene resin having excellent heat resistance and chemical resistance are used. Are known. For example, JP-A-63-2
No. 42610 and Japanese Patent Application Laid-Open No. 62-21819. Further, for example, Japanese Utility Model Publication No. 2-45594 proposes a sealing material using an expanded porous body of polytetrafluoroethylene.

[0004]

However, as a gasket for sanitary piping, which handles pharmaceuticals and the like that are strict with respect to elution of impurities and require cleaning under severe conditions,
In particular, a gasket has not yet been proposed which has been sufficiently studied in consideration of use conditions such as exposure to severe conditions for removing pyrogen as described above. The inventors initially applied a conventional polytetrafluoroethylene resin gasket for sanitary piping, which is also excellent in alkali resistance, in place of a conventional sanitary piping gasket made of silicone resin. However, gaskets for sanitary piping made of ordinary polytetrafluoroethylene resin used for conventional sealing members have a higher hardness than conventional silicone resin, so the tightening pressure of the flange part must be increased. If gas such as steam leaks, and if the flanges once tightened are retightened, it is extremely difficult to suppress gas leaks in the second and subsequent tightening without elastic recovery to the initial state. It has been found that the piping system cannot be tightly connected to completely seal gas and the like. The inventors, based on the above findings, heat resistance,
We provide a gasket for sanitary piping that has excellent chemical resistance, especially alkali resistance, and excellent elastic recovery, and we are diligently studying the purpose of completely sealing the joint of the sanitary piping system and tightly connecting the piping system. As a result, the present invention has been achieved.

[0005]

According to the present invention, there is provided an annular disk having a predetermined thickness concentrically penetrating a central portion thereof, the annular body being concentrically annularly protruding up and down. And a porous polytetrafluoroethylene having a density of 1.0 to 1.9 g / cm ³ and a porosity of 12
５０50 %, and the density of the projections is 0.3-1.4 g / cm ^3.
And a gasket for a sanitary pipe integrally formed with a porosity of 40 to 86 % at a predetermined position of a joint portion of a sanitary pipe system which can be exposed to at least an alkali solution and / or a saturated steam wet state. A sanitary piping system connection method is provided, wherein the piping system is fitted and tightly connected.

[0006]

According to the present invention, the density of the disk portion is set to 1.0 to 1.9 g / cm ³ and the density of the convex portion is set to 0.3 using porous polytetrafluoroethylene. ~
The sanitary piping gasket integrally formed at 1.4 g / cm ³ is applied to the joints such as ferrules and flanges that connect the sanitary piping system, and is fitted with good positional accuracy to connect the sanitary piping system. I do. Thereby, the gasket disk portion having the porous and specific density described above, in combination with the inherent water repellency and releasability of polytetrafluoroethylene as a gasket raw material, allows the gasket surface to penetrate into the gasket surface of the piping distribution body. In addition, the gasket material is prevented from adhering to the contact surface of the ferrule or flange. At the same time, the sanitary piping system can be connected tightly and with good sealing properties even when it is used a plurality of times, because of its high elasticity, excellent elastic recovery, and high shape restoring force. Furthermore, even in the case of repeated use a plurality of times, there is no danger of sticking to the metal surface of the joint part unlike the conventional silicone resin gasket, eliminating contamination in the piping system due to the gasket and tightly closing the sanitary piping system. Can be connected to

Hereinafter, the present invention will be described in detail. FIG. 1 is an explanatory plan view and a sectional view of one embodiment of a gasket for sanitary piping of the present invention, and FIG. 2 is a sectional explanatory view of another embodiment of a gasket for sanitary piping of the present invention. In FIGS. 1 and 2, the disk-shaped gaskets 1 and 1 ′ have upper and lower convex portions 3 and 3 ′ concentrically in the disk portions 2 and 2 ′. Such a shape is specified by the International Organization for Standardization (ISO) as a gasket for sanitary piping. In particular, it is stipulated that a gasket for a sanitary pipe can be fixed at an appropriate position so as not to cause a liquid pool or the like inside the pipe, as a gasket for a sanitary pipe which has a strict content purity. Therefore, the convex portions 3 and 3 '
It is arranged so as to match the position of a concave portion provided in a joint portion such as a flange to be used. In addition, the diameter r of the central space concentrically penetrated with the disk portion of the gasket 1 is set to be substantially the same as the inner diameter of the flange to be applied, so that there is no adhesion or accumulation of a chemical solution or the like in the apparatus. It is formed as follows. The gasket 1 'of FIG. 2 is exactly the same as the gasket of FIG. 1 except that a hook 4 for temporarily fixing the gasket to the flange is provided on the outer peripheral edge. In addition, the thickness of the disc portion after molding the gasket for sanitary piping,
Although not specified in ISO, it is usually 0.1-8m
m, preferably 0.5 to 5 mm.

The porous polytetrafluoroethylene of the present invention is obtained by making polytetrafluoroethylene porous. The polytetrafluoroethylene (hereinafter, referred to as PTFE) can be made porous by a known method. For example, a PTFE sheet is kept at a melting point or lower, at a temperature of 300 ° C. or higher, while maintaining a width and a thickness substantially. A sheet stretching method in which a craze is generated by stretching in the length direction and heat-treated to make it porous, an admixture in which a liquid lubricant such as solvent naphtha or petroleum is added to PTFE is extruded and further molded in the same manner as above. Extrusion stretching method for stretching, flammable substance calcination removal method for burning and removing flammable substance added to PTFE to make it porous.
There is a porous method such as a sintering method in which fibrous PTFE is sintered to make it porous. In addition, PTFE used for the above-mentioned porous formation
In order to prevent impurities etc. from being eluted in the reaction product etc. of the device where the gasket for sanitary piping is used, unlike the production of the gasket etc. for the conventional general device, the porous material is added without adding the inorganic substance or blending the copolymer. Preferably, it is subjected to a chemical treatment.

The porous polytetrafluoroethylene constituting the gasket for sanitary piping of the present invention has a disk portion density of 1.0 to 1.9 g / cm ³ (porosity of 12 to 50).
%), And the density of the protrusions is 0.3 to 1.4 g / cm.
³ (porosity of 40 to 86%). The density of the disk is 1.
If it is less than 0 g / cm ³ , the effect of preventing permeation decreases, and
If it exceeds 1.9 g / cm ³ , the elasticity is inferior and the conformability at the time of tightening is unfavorably deteriorated. On the other hand, the density of less than 0.3 g / cm ³ of the convex portion is difficult arrangement fixed to the shape retention is difficult joint of protrusions, especially after the mounting workability, 0.6 g / cm ³ or more is preferable . Also,
When the density of the projections exceeds 1.4 g / cm ³ , the projections become rigid,
It is not preferable because the fitting of the joint portion such as the flange and the ferrule to the concave portion is lost. In this case, in the gasket having the shape shown in FIG. 2, the density of the hook 4 is not particularly limited, and may be the same as the density of either the convex portion 3 ′ or the disk portion 2 ′. What is necessary is just to select suitably by a method.

In the present invention, the manufacture of the gasket for sanitary piping is not particularly limited. Preferably, a porous PTFE having a small density corresponding to the convex portion of the gasket is used, and heated and locally pressurized in a mold for molding into the above-mentioned shape, so that a porous material having a larger density than the convex portion is formed. It is preferable to form a disk portion made of a non-conductive PTFE.

In the sanitary piping system of the present invention, the convex portion of the sanitary piping gasket is fitted and arranged in the concave portion of the joint such as a flange as described above, and then tightened with a ferrule flange or the like, and the It is sealed without leaking the flowing material to the outside and tightly joined. In the piping system of the present invention joined as described above, at the time of manufacturing pharmaceuticals, foods and the like, usually 4 to 60 ° C. and / or 0.5 to 10 ° C.
Under a wide range of temperature and pressure of kg / cm ² (absolute pressure),
Physiologically active substances, various chemicals such as injection medicines can be circulated, and in the connection of the piping system of the present invention, when the various chemicals are circulated under the above conditions, they are sealed without leaking to the outside, and the piping system is connected. Intrusion of impurities from the outside is blocked, and there is no leaching of the gasket component of the present invention arranged in the joint portion, and it is possible to completely eliminate the contamination of impurities flowing into the piping system. In addition, in particular, in the piping system of the present invention, as described above, after production of the product, under severe conditions for extremely strict cleaning, for example, at 10 to 60 ° C.
Washing can be performed with a 0.1 to 10% by weight alkali aqueous solution, saturated steam, a combination of the alkali aqueous solution and saturated steam, or nitric acid or the like. In these washings,
In the connection of the piping system of the present invention, since the cleaning liquid and / or gas can be tightly sealed without leaking to the outside and the gasket does not deteriorate, the operation of the next step should be performed after cleaning. Can be.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. However, the present invention is not limited by the following examples. Example 1 (Production of Gasket for Sanitary Piping) PTFE was pre-crystallized by a pressure roll, and then a rubber-coated pinch roll was used.
It is stretched in the length direction to 0 to 300% and has a porosity of 40 to 86.
% Porous PTFE sheet. In a disk-shaped mold 5 having a center space portion having a diameter of 23.2 mm and an outer diameter of 50.5 mm shown in FIG. 3, a mold space 6 having an inner diameter of 23.2 mm and a thickness of 20 mm is provided in the inner mold space 6 . Each porous sheet 10 obtained above was arranged. Then, the mold is heated to 15
0 ° C, 200k from the upper part 7 of the mold 5 by hydraulic pressure
Pressure was applied at g / cm ^{2 to} 600 kg / cm ² . as a result,
At the same time as the porous PTFE sheet was formed in the shape of the concave portion 8 of the mold 5, the portion corresponding to the disk portion 9 of the mold 5 was densified.

The densities of the convex portions corresponding to the concave portions 8 of the mold 5 of each of the sanitary pipe gaskets obtained as described above are almost the same as the densities of the porous PTFE sheets obtained above. 0.3, 0.6, 1.0, 1.2, 1.4
g / cm ³ , but the discs were 1.0,
A gasket for sanitary piping having a density shown in FIG. 1 which was densified to 1.2, 1.3, 1.4, and 1.8 g / cm ^{3 and} had different densities of the disc portion and the convex portion was obtained.

Example 2 Using each of the sanitary pipe gaskets obtained in Example 1, when the tightening surface pressure was set to 300 kg / cm ² , the compression recovery rate of the disk portion of the sanitary pipe gasket was measured by an Amsler test. It was measured with a machine. The results are shown in FIG. 4 as the relationship between the gasket restoration rate and the density.
復 元 16% restoration rate, especially when the density of the disc is 1.2 g
/ Cm ³ or more gave good results.

Comparative Example 1 Porous PTFE having a porosity of 90% in the same manner as in Example 1.
A sheet was prepared and used to obtain a gasket for sanitary piping having a convex density of about 0.25 g / cm ³ and a disk density of 0.6 g / cm ^{3 in} the same manner as in Example 1. . The compression recovery rate of the disk portion of the gasket for sanitary piping obtained in the same manner as in Example 2 was measured. As a result, as shown in FIG. 4, the restoration rate was as low as 6%, and the gasket after the measurement had a large deformation.

Comparative Example 2 Instead of the porous PTFE sheet of Example 1, a porous P
The raw material PTFE used for manufacturing the TFE sheet was heated and melted at 380 ° C. in the same mold as in Example 1 to manufacture a PTFE gasket having the same shape. The obtained PTFE
In the gasket, the densities of the convex portion and the disc portion are both about 2.1.
g / cm ³ . The compression / restoration ratio was measured in the same manner as in Example 2. The result is shown in FIG. It is clear from FIG. 4 that only a lower recovery rate can be obtained than any of the gaskets obtained in Example 1.

Example 3 Density of convex portion obtained in the same manner as in Example 1 1.0 g / cm
^{In step 3} , a 1-inch gasket for sanitary piping having the same disk shape with a disc density of 1.3 g / cm ³ was provided in a part of the saturated steam piping system shown in FIG. That is, in FIG. 5, the pipe 12 branched from the saturated steam supply pipe 11
Is connected to a T-shaped joint 14 via a ball valve 13,
Further, one side of the T-shaped joint 14 has a diaphragm valve 1.
5 was connected, and a pipe 16 was connected to the other joint side. Further, a pipe 17 was further connected to the diaphragm valve. In the saturated steam pipe configured as described above, the ferrule on which the 1-inch gasket is arranged is installed at the connection portion 18 between the diaphragm valve 15 and the T-shaped joint 14, and 1.9
The steam at a pressure of kg / cm ² was passed at a frequency of 2 to 4 times a week for about 2 hours per time. This operation was continued for 6 months. During this period, the gasket placed every month was taken out and inspected, and then placed again at the same position and used repeatedly, but no particular leakage of steam or the like occurred. Also,
No change or abnormality was observed in the shape and appearance of the gasket taken out and inspected.

Comparative Example 3 Example 3 was repeated except that the porous PTFE gasket obtained in Comparative Example 1 was arranged in a ferrule and installed in the connecting portion 18.
Saturated steam was passed in the same manner as described above. As a result, the shape of the gasket itself was poor, and the mounting operation was difficult. In addition, the gasket after pressurization was protruded to the inner and outer diameter sides, and could not be used continuously.

Example 4 The same 1-inch gasket for sanitary piping as in Example 3 was immersed in a 2% by weight aqueous solution of caustic soda for one week, washed with water, and then placed in the piping system shown in FIG. That is, in FIG. 6, a filter 22 loaded with a filter medium 30 for removing dust and the like in the chemical solution is connected to a chemical supply pipe 21, and a pipe 23 connected to an outlet side of the filter 22 and a T-shaped joint 25. Are connected via a diaphragm valve 24. A steam supply pipe 27 is connected to one joint side of the T-shaped joint 25 via a diaphragm valve 26,
A chemical solution discharge pipe 28 is connected to the other joint side.
In the piping system configured as described above, the ferrule on which the gasket for 1-inch sanitary piping described above was disposed was installed at the connection portion 29 between the T-shaped joint 25 and the chemical solution discharge pipe 28. This piping system is first sterilized by autoclave with high-pressure saturated steam, and then the chemical is continuously supplied from the piping 21 through the pipe 21.
Time supplied. No impurities were observed in the chemical discharged through the piping system. Thereafter, the gasket was taken out from the connection portion 29, again subjected to alkali immersion and water washing in the same manner as described above, and similarly, the operation of disposing the gasket in the piping system was repeated once a week for six months.
As a result, even after the operation after six months, there is no occurrence of leakage of vapor, chemical solution, etc., or sticking of the gasket to the ferrule, and the used gasket has elasticity,
No abnormal deformation was observed. In addition, no impurities were mixed into the chemical solution.

Comparative Example 4 The PTFE gasket obtained in Comparative Example 2 was immersed in an alkaline aqueous solution in the same manner as in Example 4, washed with water, placed in a ferrule, placed at the connection part 29, and sterilized by autoclaving.
The drug solution was distributed. As a result, the gasket was locally deformed abnormally due to the creep phenomenon, and did not adhere to the flange surface during repeated use, causing leakage of steam and chemicals.

Comparative Example 5 A commercially available gasket made of silicone resin was used in Example 4.
After immersion in an aqueous alkali solution as described in the above, water washing was performed, the ferrule was arranged, and the connection portion 29 was placed. The autoclave sterilization was performed in the same manner as in Example 4, and the drug solution was allowed to flow. As a result, when the gasket was taken out of the connecting portion 29 after the first operation, a part of the silicon gasket adhered to the pipe ferrule portion, and the gasket surface was peeled off, so that repeated use was impossible.

As is clear from the above Examples and Comparative Examples, the gasket for sanitary piping according to the present invention has a high recovery rate against the tightening pressure of the joint portion, has an excellent shape recovery force, and can be used even when it is used repeatedly a plurality of times. Also has excellent sealing properties. Also, it has high durability against superheated steam and alkali, and does not adhere to the fittings of the gasket even after repeated washing and use. Therefore, the connection of the sanitary piping system of the present invention using the same completely shuts off the flowing chemical solution in the piping system from the outside, and does not mix impurities from the outside and impurities discharged from the gasket. On the other hand, the connection of a piping system using a conventional PTFE gasket or a porous PTFE gasket outside the specific range of the present invention has a low restoration rate with respect to the applied pressure, and there is a gas leak from the beginning, or several repetitions. Leakage of gas etc. already occurred by use. Further, it can be seen that in the case of a commercially available silicon resin gasket conventionally used, the gasket sticks to the joint fitting or causes inconvenience such as mixing impurities into the flowing liquid.

[0023]

According to the method for connecting a sanitary piping system of the present invention, by applying a specific sanitary piping gasket to a joint portion of a piping system, impurities are not eluted in a production device for pharmaceuticals and the like. The piping system of the apparatus can be tightly connected to completely seal the flowable material in the piping system. Furthermore, the method for connecting a sanitary piping system of the present invention is excellent in heat resistance, chemical resistance such as acid and alkali, and is tight even under severe cleaning conditions such as high-concentration alkali cleaning essential for sanitary piping systems. Since a proper connection can be maintained, the flowable material in the sanitary piping system can be stably sealed for a long period of time, which is industrially extremely effective.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view and cross-sectional view of one embodiment of a gasket for sanitary piping of the present invention.

FIG. 2 is an explanatory sectional view of another embodiment of the gasket for sanitary piping of the present invention.

FIG. 3 is an explanatory cross-sectional view of a mold used for manufacturing a gasket for sanitary piping in an embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the density of the disk portion of the gasket for sanitary piping of the present invention and the restoration rate related to compression by surface pressure.

FIG. 5 is an explanatory view of a saturated steam circulation piping system according to one embodiment of the present invention.

FIG. 6 is an explanatory view of a chemical liquid distribution piping system according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Gasket for sanitary piping 2 Disk part 3 Convex part 4 Hook 5 Mold 6 Mold space 7 Upper part 8 Depression 9 Disk part 10 Porous sheet 11, 12, 16, 17, 21, 23, 27, 28 Pipe 13 Ball valve 15, 24, 26 Diaphragm valve 18, 19 Joint part 22 Filter 30 Filter material

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahisa Ueda 541-1, Shimouchi deities launched in Mita Plant, Mita City, Hyogo Prefecture Inside Mita Plant of Nippon Pillar Industry Co., Ltd. (72) Inventor Takashi Murakami Nonaka, Yodogawa-ku, Osaka, Osaka Minami 2-chome 11-48 Nippon Pillar Industry Co., Ltd. Headquarters (56) Reference US Patent 4070219 (US, A) WO 89/11608 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , (DB name) F16F 23/00-25/02

Claims (2)

(57) [Claims] 1. A disk-shaped annular body having a predetermined thickness concentrically penetrating a central portion, having a convex portion above and below the disk portion concentrically with the annular body, and comprising a porous polytetrafluorocarbon. The density of the disc is adjusted to 1.0 to 1.9 g / c by ethylene.
m ³ and porosity to 12 to 50 %, and the density of the projections to 0.1.
A sanitary pipe gasket integrally formed with 3-1.4 g / cm ³ and a porosity of 40-86 % is provided with a sanitary pipe whose inside can be exposed to a wet state of at least an alkaline solution and / or saturated steam. A method for connecting a sanitary piping system, wherein the piping system is tightly connected by fitting and arranging the piping system at a predetermined position of a joint portion of the system. 2. A disc annulus, to claim 1 is obtained by using a mold of the same inner diameter as the inner diameter of the annular raw material and the gasket having the same inner diameter as the inner diameter of the gasket How to connect the described sanitary piping system.