JPH11315994A - Fluid passage for covering liquid repelling thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure loss of a fluid by coating a low surface energy material comprising fluoroalkoxysilane as a main component, and covering a liquid repelling thin film having high liquid repelling property on an inner surface of a liquid passage. SOLUTION: In a case where low surface energy material is coated only on inner surfaces of a suction passage 2 and a discharging passage 3, masking is carried out on a part where coating is not necessitated beforehand, and coating liquid is prevented from sticking on a part where the masking is carried out. In a large passage apparatus, masking is carried out only on an inner surface of the apparatus, coating liquid is filled into the apparatus, dipping is eliminated, and coating work is carried out so as to prevent coating liquid from sticking on a surface of the apparatus. Since liquid repelling thin film having high liquid repelling property on inner surfaces of the suction passage 2 and the discharging passage 3 of a pump is covered by the coating work, pressure loss of the fluid which flows the fluid passage is reduced, and an efficiency of the pump is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid passage in which a liquid repellent thin film is coated on an inner surface of a passage of a device for flowing (conveying) a liquid such as water, liquid fuel, or oil.

[0002]

2. Description of the Related Art FIG. 3 shows that a fluid passage in which a Teflon resin lining (Teflon is a trade name of one of fluororesins) having a film thickness of 15 μm or more is provided on the inner surface of a pipe made of synthetic resin, The conventional example applied to the suction passage 2 and the discharge passage 3 is shown. The suction passage 2 and the discharge passage 3 are integrally formed in a cylindrical housing 7 of the pump 1, and the housing 7 is divided into a pump chamber 9 and a motor chamber 10 by a partition wall 8. A rotating shaft 15 is rotatably supported by a bearing 14 at the center of the motor chamber 10, and a stator coil 12 is wound around a plurality of stator cores 11 around the rotating shaft 15. The tip of the rotating shaft 15 extends through the partition 8 into the pump chamber 9, and the rotor 17 is fixed to the tip of the rotating shaft 15.
A rotating blade 18 is formed on one side of the rotor 17, and a rotor magnet 19 is provided on the other side of the rotor 17.

The Teflon resin lining shown in FIG. 3 has a low dimensional accuracy due to the lining (lining) process, and its use is limited (not suitable for a fluid passage for precision equipment).
Since it is 5 μm or more, the inner diameter of the passage becomes smaller,
The flow rate decreases. In addition, when the dimensions of the passage are relatively small, it is difficult to apply a Teflon resin lining to the inner surface, and the thickness of the lining layer is not uniform, and the pressure loss due to the change in the cross-sectional area of the passage. Occurs. Since the Teflon resin lining has a large film thickness, a large amount of Teflon resin is required to cover the entire passage.

[0004]

SUMMARY OF THE INVENTION The present invention reduces the friction on the passage wall by improving the liquid repellency (water repellency or oil repellency) of the inner surface of the passage in the fluid passage of a device for handling a fluid. Another object of the present invention is to reduce the pressure loss of a fluid.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a fluid passage having an inner surface coated with a low surface energy material containing fluoroalkylsilane as a main component. A first configuration is that a fluid passage covered with a liquid-repellent thin film having high liquid-repellency is formed. According to a second aspect of the present invention, in the first aspect, a composition comprising a fluoroalkylsilane, methyltetraethoxysilane, n-butanol, distilled water, phosphoric acid, and ethanol is coated as a coating liquid.

[0006]

1 and 2 show an embodiment of a fluid passage covered with a liquid-repellent thin film according to the present invention. In the magnetic coupling pump 1 of FIG. 1A, the same members as those of the conventional example of FIG. 3A are denoted by the same reference numerals as those of the conventional example, and the description thereof will be omitted. The surface of the solid has a higher energy state than the inside due to a change in the electronic state and relaxation of the atomic arrangement due to the breaking of atomic bonds there. This excess energy of the surface is called surface energy, and the low energy surface has liquid repellency,
Each of the high energy surfaces has lyophilic properties and is used as a measure for measuring the adhesive strength.

In the embodiment of the present invention, a thin film coating (painting) of a low surface energy material having a thickness of 1 μm or less is applied to the inner surfaces of the fluid passages such as the pipe, the suction passage 2 and the discharge passage 3. Therefore, the inner surface of the fluid passage is significantly reduced in energy, the liquid repellency is greatly improved, and the pressure loss of the fluid flowing in the fluid passage is reduced. Fluorine-based resins and silicone-based resins are known as low surface energy substances. In the embodiment of the present invention, a coating liquid having a composition containing fluoroalkylsilane as a main component shown in the table of FIG. Used. Further, a fluoroalkylsilane as a low surface energy substance, a Teflon-based coating liquid as a fluorine-containing substance, or KP80 manufactured by Shin-Etsu Chemical Co., Ltd.
A coating solution of 1M can be used.

FIG. 2 (b) shows a process of coating a low surface energy substance on an inner surface of a passage of a device (passage device) which handles a fluid.
As shown in, degreasing / washing, dipping (injection), lifting,
Air blow (centrifugal separation), drying and baking. When coating the low surface energy substance only on the inner surfaces of the suction passage 2 and the discharge passage 3 shown in FIG. 3A, masking is performed in advance on a portion that does not require coating, and a coating liquid adheres to the masked portion. Keep it away. As for the large passage equipment as shown in Fig. 3 (a), the masking is applied only to the inner surface of the equipment, the coating liquid is injected into the equipment, the immersion is omitted, and the coating work is performed so as not to adhere to the equipment surface. Do. The coating covers the inner surfaces of the suction passage 2 and the discharge passage 3 of the pump with the liquid-repellent thin film having high liquid repellency, so that the pressure loss of the fluid flowing through the fluid passage is reduced and the efficiency of the pump is improved.

When the passage of the equipment is extremely small in diameter, a vacuum vessel is used for the immersion (injection) step, the passage equipment is placed in a vacuum vessel, the inside of the vacuum vessel is evacuated, and then the coating liquid is filled. By vibrating or rotating the container, the coating liquid is completely attached to the small-diameter passage.
In this way, the coating of the low surface energy substance can be applied to a complicated and extremely small passage, and the excess coating liquid is removed by the air blow (centrifugal separation) process, so that the thickness of the coating thin film is reduced. The pressure loss of the fluid flowing through the fluid passage is reduced.

[0010]

EXAMPLE An example of the coating step will be described. In the first step, the passage device is degreased with a solvent such as isopropyl alcohol and ethanol, and then washed. In the second step, a fluoroalkylsilane (FA
2) The coating liquid having the composition shown in FIG. 2 (a) as a main component is placed in a dipping container, and the passage device is immersed in the coating liquid. The coating liquid is applied to the entire surface inside.

In the third step, the passage device is lifted from the immersion container. In the fourth step, an excess amount of the coating liquid remaining in and adhering to other portions in the passage is removed using an air blow device or a centrifuge. At the time of air blow, compressed air of 3 kg / cm ² is blown for only about 10 seconds, and at the time of centrifugal separation, it is rotated at a rotation speed of 2000 rpm for about 20 minutes.

In the fifth step, in order to volatilize the solvent in the coating liquid, it is placed in a drying chamber at 100 ° C. for only about 10 minutes and dried. In the sixth step, the passage device is placed in an electric furnace or the like and fired at a temperature not higher than the heat-resistant temperature. Although it depends on the size and material of the passage device, it is generally baked for 20 minutes at a temperature of 250 ° C. Through the above steps, a fluoroalkylsilane-coated thin film is obtained on the inner surface of the passage of the passage device.

[0013]

The fluid passage coated with the liquid-repellent thin film of the present invention is a fluid passage in which a coating is applied to the inner surface of the passage of a device for handling a fluid, wherein the fluid passage is coated with a low surface energy substance mainly composed of fluoroalkylsilane. Then, the inner surface of the liquid passage is coated with a liquid-repellent thin film having a higher liquid-repellent property (water repellency or oil repellency). Therefore, the friction at the passage wall is reduced, the pressure loss of the fluid flowing through the fluid passage is reduced, and the efficiency of the device handling the fluid is improved. Further, the present invention can be applied to a complicated and small-diameter fluid passage, and the fluid passage of a precision instrument can be coated with a low surface energy substance to increase the efficiency.

[Brief description of the drawings]

FIG. 1 (a) is a sectional view of an embodiment in which the present invention is applied to a suction passage and a discharge passage of a magnetic coupling pump, and FIG. 1 (b) is a sectional view showing a state in which the present invention is applied to a pipe. is there.

FIG. 2 (a) is a table showing the composition of a coating liquid used in an embodiment of the present invention, and FIG. 2 (b) is an explanatory diagram showing a coating process in the embodiment of the present invention. .

FIG. 3 (a) is a cross-sectional view in which a conventional lining is applied to a suction passage and a discharge passage of a magnetic coupling pump.
(b) is a sectional view showing a state where a conventional lining is applied to a pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic coupling pump 2 Suction passage 3 Discharge passage 21 Low surface energy material thin film

Claims (2)

[Claims] In a fluid passage having a coating formed on the inner surface of a passage of a device for handling a fluid, a low surface energy substance containing fluoroalkylsilane as a main component is coated to increase the liquid repellency of the inner surface of the liquid passage. A fluid passage covered with a liquid thin film. 2. The fluid passage coated with a liquid-repellent thin film according to claim 1, wherein a composition comprising a fluoroalkylsilane, methyltetraethoxysilane, n-butanol, distilled water, phosphoric acid, and ethanol is coated as a coating solution.