JP2004083772A - Pressure pulsation absorbing foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulsation-preventing apparatus used for reducing the pulsation of a pressure fluid in a pressure piping system, particularly a pulsation absorbent efficiently absorbing pressure and flow rate pulsation of the pressure fluid which flows the interior of piping. <P>SOLUTION: The pressure pulsation absorbing foam enabling absorption of the pulsation is formed by arranging foam composed of a fluorine rubber elastomer and having closed cells in a pressure circuit. Thereby, pulsation absorption of a frequency having a broad width is made possible. <P>COPYRIGHT: (C)2004,JPO

Description

【００１６】
圧力脈動吸収体の効果
図２に示すような試験機をもって表２に示すデータを計測した。
【表２】

【００１７】
【発明の効果】
上記のような構成によって、以下に示す優れた効果が得られる。
本発明の圧力脈動吸収発泡体は、簡単な構造であり小型化を実現するので配管や機器の中にインラインで容易に組込みあるいは脱抜することができ省スペースを果たす。
また、弾性体故に造形が自由であるから流体の流れ抵抗が少ない形状が可能であり、圧力損失が極めて小さいものとなる。
さらに、本発明の圧力脈動吸収発泡体は脈動圧力に対して柔軟に容積変化するので高い周波数から低い周波数まで広い幅の周波数の脈動吸収が可能となる。
また本発明の圧力脈動吸収発泡体は、独立気泡を有しその気泡が樹脂でおおわれ、さらに構成する弾性体は耐油性、耐薬品性、耐燃料油性、耐熱性にすぐれるフッ素ゴムであることから、耐久性についても十分満足するものである。
【図面の簡単な説明】
【図１】本発明の実施例を示す略断面図である。
【図２】データ計測の試験機の略図である。
【図３】本発明を用いない従来の実施例を示す略断面図である。
【符号の説明】
１　　圧力管路
２　　凹部
３　　圧力脈動吸収発泡体[0001]
[Industrial application fields]
The present invention relates to a pulsation prevention device used for reducing pulsation of pressure fluid in a pressure line system, and more specifically, a pulsation absorber that efficiently absorbs pressure and flow rate pulsation of pressure fluid flowing in a pipe. About.
[0002]
[Prior art]
Conventionally, as means for suppressing the pulsation of pressure fluid, a bladder or diaphragm made of synthetic rubber is used for an accumulator to which a bladder or a diaphragm is attached. In the insulator, the bellows is used to suppress (absorb) the pressure by changing the volume of the sealed gas or the spring in response to the pressure fluctuation in the fluid.
Among them, as an inline accumulator, there is an accumulator having a configuration as shown in FIG.
In this accumulator, end caps 3a are respectively attached to outer cylindrical portions 3 formed in a substantially cylindrical shape, and a bulging cylindrical bladder 4 made of synthetic rubber connected to the end caps 3a at both ends is disposed. The inside of the bladder 4 is used as a pressure fluid flow path, and a gas 5 such as N2 high-pressure gas is sealed between the outer cylinder portion 3 and the bladder 4, and the bladder 4 is excessively deformed on the inner peripheral side of the bladder 4. A configuration in which an inner tube 6 in which a large number of holes are cut in order to suppress the pulsation absorbing structure is generally used.
[0003]
[Problems to be solved by the invention]
However, such in-line type accumulators are listed as the biggest drawbacks of their complicated and expensive structure, and the use is limited, and the general maintenance such as troublesome maintenance associated with nitrogen high-pressure gas is common. It has various disadvantages that cannot be realized.
In order to eliminate such drawbacks, a simple structure (not shown) that reduces the pulsation of fluid pressure by installing foam rubber in the pressure fluid flow path has been considered. If this is repeated, the air in the foamed rubber bubbles leaks into the liquid, or the permeation of the liquid into the foamed rubber permeates through the rubber. Therefore, this has not yet become widespread.
In view of such drawbacks, the present invention has invented a pulsation absorber based on an unconventional concept that is simple and has a wide range of applications, and absorbs a pulsation surge of a fluid in a pressure line. Provide the body.
[0004]
[Means for Solving the Problems]
Provided is a pressure pulsation absorbing foam which can absorb pulsation by disposing a foam having closed cells made of a fluororubber elastic body in a pressure circuit.
The purpose of the pressure pulsation absorbing foam used in the present invention can be achieved by heating and foaming the fluororubber composition.
[0005]
The polymer constituting the fluororubber composition used in the present invention is generally a binary fluororubber obtained by copolymerizing vinylidene fluoride and tetrafluoroethylene.
Or a ternary fluororubber copolymerized with vinylidene fluoride and tetrafluoroethylene by adding hexafluoropropylene, or a ternary fluororubber polymerized by adding perfluoroalkoxyethylene or trifluoromethoxyethylene to vinylidene fluoride and tetrafluoroethylene. These polymers are preferred, especially when the liquid in the pressure circuit is fuel oil.
[0006]
The thermally expandable microcapsule constituting the fluororubber composition used in the present invention is composed of a liquid gas encapsulated in a resin shell, and its particle size is 2 to 50 microns. By heating this, It expands to a volume of about 5 to 100 times.
As the liquid gas, low molecular weight hydrocarbons are generally used, and examples thereof include ethylene, propane, butane, isobutane, and pentane.
[0007]
As the resin constituting the shell, a thermoplastic resin is generally used, and polyethylene, polypropylene, styrene resin, acrylic resin, vinylidene chloride resin, acrylonitrile resin, PET, PBT, fluororesin, polyvinyl alcohol, and ethylene vinyl alcohol are used together. There are polymerized resins. Preferably, a resin having gas barrier properties such as PET, vinylidene chloride resin, polyvinyl alcohol, ethylene vinyl alcohol copolymer resin and the like is preferable.
The amount used is generally 1 to 30 parts per 100 parts by weight of the fluororubber polymer.
[0008]
The fluororubber composition used in the present invention must contain a compounding agent necessary for vulcanization. Generally, a vulcanization system generally used for fluororubber may be selected. Examples of the vulcanization system include polyol vulcanization, polyamine vulcanization, and peroxide vulcanization.
The fluororubber composition used in the present invention can optionally contain a reinforcing agent, a filler, a lubricant, a processing aid and the like as necessary.
[0009]
The method for preparing the fluororubber composition used in the present invention is not particularly limited, and the fluororubber composition can be prepared by adding the above-mentioned components and mixing them with an ordinary kneader such as a kneader, Banbury mixer, open roll or the like.
The rubber composition thus prepared is usually vulcanized and foamed at 100 to 220 ° C. for about 2 to 30 minutes.
[0010]
The manufacturing method of the product may be to vulcanize and foam the preformed rubber composition by open vulcanization, or to prepare the amount of the composition reduced by that amount in anticipation of the amount of gas foaming into the cavity. Alternatively, it may be formed into a cavity shape simultaneously with heating and foaming. The foam thus formed may be subjected to a heat treatment at a temperature of 80 ° C. to 220 ° C. for about 30 minutes to 24 hours as necessary.
[0011]
As described above, the present invention arranges a foam pressure pulsation absorbing foam having closed cells in a pressure line system to circulate a pressure fluid, and the pressure pulsation absorbing foam is, for example, a hydraulic circuit. The pulsation and surge pressure of the pressure fluid generated by various control devices inside are extremely effectively suppressed.
[0012]
The foam of this pressure pulsation absorbing foam holds a gas of closed cells inside and has a balloon shape rich in elasticity. Each absorber changes its volume each time depending on the fluid pressure and absorbs the pressure change.
This absorption action is that the whole part of the pressure pulsation absorbing foam works efficiently, and the individual bubble parts flexibly change the bubble volume changed in the vicinity of the contact in a manner similar to the state in which the gas is dispersed in the liquid. The fluid having no catching and no pulsation or pressure change can be pumped to another device.
[0013]
As long as the fluid in the pressure circuit is generally fluid resistant to fluoro rubber, it can be used for all hydraulic fluids such as engine oil, ATF oil, brake oil, and machine oil without any problem in practical use. It can also be used for gasoline and fuel oil.
[0014]
【Example】
Examples of the present invention will be described below.
In FIG. 1, a concave portion 2 is provided on a side portion of the pressure line 1 and the pressure pulsation absorbing foam 3 of the present invention is attached to the concave portion 2. Here, a thin film outer shell is applied to a large pulsation or a strong impact. The structure can exhibit a sufficient tolerance and can provide an effective absorption effect. Also, with this structure, good exchangeability can be obtained by arranging the back cover and the like, and wide versatility can be obtained.
[0015]
Composition of pressure pulsation absorbing foam [Table 1]

[0016]
Effect of Pressure Pulsation Absorber The data shown in Table 2 was measured using a testing machine as shown in FIG.
[Table 2]

[0017]
【The invention's effect】
With the above configuration, the following excellent effects can be obtained.
Since the pressure pulsation absorbing foam of the present invention has a simple structure and realizes downsizing, the pressure pulsation absorbing foam can be easily incorporated or removed in-line from a pipe or equipment, thereby saving space.
Further, since it is an elastic body and can be shaped freely, a shape with less fluid flow resistance is possible, and the pressure loss is extremely small.
Furthermore, since the volume of the pressure pulsation absorbing foam of the present invention flexibly changes with respect to the pulsation pressure, it is possible to absorb pulsations of a wide frequency from a high frequency to a low frequency.
In addition, the pressure pulsation absorbing foam of the present invention has closed cells and the cells are covered with resin, and the further elastic body is fluororubber excellent in oil resistance, chemical resistance, fuel oil resistance and heat resistance. Therefore, the durability is sufficiently satisfied.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a schematic diagram of a data measurement testing machine.
FIG. 3 is a schematic cross-sectional view showing a conventional example not using the present invention.
[Explanation of symbols]
1 Pressure line 2 Recess 3 Pressure pulsation absorbing foam

Claims (5)

In the pressure pulsation absorbing foam for absorbing the pulsation placed in the pressure circuit,
A pressure pulsation-absorbing foam characterized in that it is formed of a binary fluororubber composed of vinylidene fluoride or tetrafluoroethylene or a foam composed of a fluororubber copolymerized with a monomer copolymerizable with these monomers. In the pressure pulsation absorbing foam for absorbing the pulsation placed in the pressure circuit,
Pressure pulsation-absorbing foam characterized by being formed of a ternary fluororubber composed of vinylidene fluoride, tetrafluoroethylene or hexafluoropropylene, or a foam composed of a fluororubber copolymerized with these monomers. body. 3. The pressure pulsation absorbing foam according to claim 1, wherein the foam is composed of a fluororubber composition containing thermally expandable microcapsules, and has closed cells formed by heating and foaming the composition. body. 3. The pressure pulsation absorbing foam according to claim 1, wherein the foam has a gas content of 20% to 90%. The pulsation absorbing foam according to any one of claims 1, 2, 3, and 4, wherein the fluid in the pressure circuit is hydraulic oil or fuel oil.

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