JP2878367B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flow meter, and particularly to a flow meter having a long service life which is particularly suitable for applications requiring high wear resistance and corrosion resistance by using specific ceramic parts. It relates to a flow meter.

[Conventional technology]

Conventionally, plastic and stainless steel have been used for gears and casings for flowmeters.However, metal products have the drawback that they have high specific gravity and are noisy, and lightweight plastics have a short life. However, their service life is short and their use is limited due to their greatest drawback of being poor in corrosion resistance.

[Problems to be solved by the invention]

As described above, conventional materials for flow meters have abrasion resistance,
The corrosion resistance was weak, and there was a problem with the life.

An object of the present invention is to provide a flow meter device excellent in wear resistance, corrosion resistance, and life by applying a specific ceramic material to a flow meter component.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a casing, an elliptical gear provided in the casing and rotating according to the flow of a fluid to be measured, and a rotating shaft for bearing the elliptical gear are provided. And, in a flow meter having a bearing that supports a rotating shaft, the casing, the elliptical gear, the rotating shaft, at least one part of the bearing, the average particle diameter of 0.1μm ~ 100μm SiC or TiN and metal Si powder from Porous Si ₃ N ₄ having a density of 5 g / cm ³ or less and a porosity of 5 to 30 vol%, obtained by reacting the formed body with Si ₃ N ₄ having an average particle size smaller than the SiC or TiN obtained by nitriding. Join
It is made of a SiC or TiN reaction sintered ceramic material. The flowmeter having characteristics such as abrasion resistance, corrosion resistance, thermal shock resistance, and low-cost production can be achieved by using the reaction sintered ceramic material.

Here, the dimensional change during sintering of the reaction-sintered ceramics is as small as about 1%, which is 1/10 to 1/100 as compared with the dimensional change during sintering of normal-pressure sintered ceramics of about 15%. Since it is small and does not deform during sintering, it can be used without processing or almost without processing, so that the processing cost can be reduced and the cost of the product can be reduced.

The present invention, as shown in FIG.
m, consisting of SiC or TiN (21), Si ₃ N ₄ (22) having an average particle size smaller than SiC or TiN, and pores (23) having a porosity of 5 to 30 vol% and a maximum pore size of 30 μm or less. The particle size is
The fluid used adheres to the small pores between the Si ₃ N ₄ (22) particles smaller than C or TiN, such as 24, in the pores and on the surface of the Si ₃ N ₄ portion 22, as in 24, and can provide a lubricating effect. It is possible.
In particular, the presence of the micropores for retaining oil and the like enhances the oil retention and provides a lubricating effect.

In addition, by impregnating and adhering oil, solid lubricant, resin, metal, and the like in the sintered body, it is possible to improve sliding characteristics and to prevent adhesion of a used fluid.

Sliding surface of the second view of SiC or TiN particles 21 and the Si ₃ N ₄ particles 22 smoothing or by lapping, the Si ₃ N ₄ particles 22
By making the concave from 0.1 μm to about 1 μm, it is possible to further enhance the retention of the lubricant. With this concave portion, the lubricant collects and the lubricating effect can be further improved.

In the present invention, 22 Si ₃ N ₄ particles are SiC or TiN
And Si ₃ N produced by nitriding the compact of metal Si powder
₄ particles, and the resulting Si ₃ N ₄ particles are 3 μm
The following uniform and fine particles having a pore diameter of 30 μm or less can be easily obtained. In this method, the pores have a diameter of 1 μm.
m or less, the contact area with the substance in the pores increases, the retention of oil and the like can be further improved, and the abrasion resistance is excellent, and the contamination due to the lubricant falling off can be prevented. .

Here, oil, graphite, molybdenum disulfide, tungsden disulfide, titanium disulfide, BN, fluororesin, tellurium disulfide, selenium disulfide, barium hydroxide, iron chloride, silver iodide, torque, borax, kaolin, oxidation A lubricant in which one or more solid lubricants selected from lead, vermulite, paraffin wax, stearic acid, Fe-Mn lead phosphate and the like can be used. This is because oil alone may run out of oil during long-term use at high temperatures, but if it is a mixture of oil and a solid lubricant, there is no need to worry about it and reliability and durability are excellent. is there.

In particular, the use of porous Si ₃ N ₄ bonded ceramics having a density of 5 g / cm ³ or less and a porosity of 5 to 30%, which is formed by nitriding a molded body made of the Si powder of the present invention and SiC or TiN powder, An extremely excellent wear-resistant member is obtained. However, the porosity is
It has been confirmed that when it exceeds 30%, the amount of wear increases sharply. Conversely, it has been confirmed that when the porosity is less than 5%, the amount of wear also increases. The reason for this is that, by having an appropriate amount of pores, the pores provide an oil retaining effect, and an oil film is formed, so that no galling occurs due to a lubricating effect and the wear resistance is excellent. Porosity is 30vol
%, The amount of wear increases because the mechanical strength between the particles decreases. Therefore, in the present invention, by using a ceramic sintered body having a porosity of 30 vol% or less, preferably 5 to 30 vol%, a member for a flow meter excellent in wear resistance and corrosion resistance can be obtained.

Inertia force for operating the flowmeter gear is always generated. In the present invention, the weight is reduced by using ceramics having a density of 5 g / cm ³ or less, and the inertia force is reduced by a factor of 1 / compared to conventional metal products.
Can be reduced from 2 to 1/3. This enables high-speed operation with low noise.

In the present invention, SiC or TiN is because when the particles 21 in FIG. 2 support the sliding partner, a material excellent in wear resistance is good, and SiC or TiN is formed from metallic Si. Due to the good covalent bonding with the resulting Si ₃ N ₄ , the bonding force is extremely strong and particles do not easily fall off.

In the present invention, the average particle size of SiC or TiN is 0.1 to 100
It is preferably set to μm. This is because if it is smaller than 0.1 μm, SiC or TiN easily falls off. Also 10
If the particle size is larger than 0 μm, the particles are liable to fall off and cause contamination. In particular, when the thickness is 5 to 20 μm, it is effective for supporting the partner material, and is most suitable for preventing the particles from falling off. Similarly, whiskers and fibers can be used.

In the present invention, in particular, a porous Si ₃ N ₄ bonded SiC formed by nitriding a compact formed of a metal Si powder and a SiC powder.
Preferably, the member is a ceramic member. By manufacturing an elliptical gear or the like from Si ₃ N ₄ bonded SiC ceramics obtained by nitriding the molded body, a sintered body can be obtained with a dimensional change rate of 0.1% or less during sintering.
It can be manufactured with almost no complicated gears or the like. SiC has a small coefficient of thermal expansion and is excellent in corrosion resistance, thermal conductivity and abrasion resistance, and Si ₃ N ₄ is a ceramic having a small coefficient of thermal expansion and excellent corrosion resistance.

According to the present invention, a highly corrosive chemical liquid or chemical can be used, and the fluid temperature can be increased to 500 ° C. or higher. Therefore, even if the viscosity of the fluid at room temperature is high, the fluid is heated to reduce the viscosity. This makes it possible to use the flowmeter lower, which is extremely useful for expanding the application of the flowmeter, improving the quality, and extending the service life.

[Action]

In the present invention, wear resistance and corrosion resistance can be significantly improved and weight can be reduced by using ceramics for the elliptical gear for a flow meter. Furthermore, as a result, it is possible to refine the flow measurement and expand the measurable range. It is also possible to impart non-magnetism and conductivity. For this reason, mechanical parts for various flow meters, gears, casings, rotating shafts,
It can be used for bearings and seals, and can improve equipment quality and life. The flow meter can also be used under high corrosion conditions, for example, for Na / K, molten metal, concentrated sulfuric acid, concentrated nitric acid, molten alkali, liquid nitrogen, LPG, oil, and organic solvents.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 80 parts by weight of metal Si powder having an average particle size of 0.9 μm and an average particle size of 2
Using a raw material having a blending ratio of 20 parts by weight of SIC powder of μm, mixed with methanol in a pot mill and dried, and then added 10 parts by weight of polyethylene wax,
The mixture was kneaded at 5 ° C. for 5 hours using a pressure kneader. The mixture was pulverized and press-molded at 150 ° C. and 1000 kg / cm ³ in a mold having the shape of the elliptical gear 2. After removing the wax content of the molded body, the molded body was subjected to a heat treatment in nitrogen gas at 1380 ° C. for a long time in a stepwise manner. Two elliptical gears 2 having a porosity of 12% were produced by such a method. Here, the rate of dimensional change from the compact to the sintered body at this time was as small as 0.1% or less, and a product excellent in dimensional accuracy was obtained. Stainless SU for comparison
The elliptical gear 2 was manufactured by S316.

Then, it is incorporated in the actual flow meter shown in FIG.
500rpm, discharge flow rate 2000 / h, fluid is continuous 3000 with water
A real machine test of time operation was performed. After the test, the flow meter was disassembled and the amount of wear was measured. Table 1 shows the results.
From this, it was confirmed that the product of the present invention was superior in wear resistance as compared with the conventional material.

The flow meter will be briefly described with reference to FIG. 1-a and FIG. 1-b, which is a cross-sectional view taken along line AA of FIG. 1. The casing 1 is provided in the casing 1 and rotates according to the flow of the fluid to be measured. Elliptical gear 2 and a rotating shaft 4 for bearing the elliptical gear 2
And a bearing 3 that supports the rotating shaft 4. Based on the rotation of the flow meter rotor (spheroidal gear) 2, a detection target (for example, a detection magnet) 5 buried in the end face of the flow meter rotor is provided. It is configured to detect that it faces a detection element (pickup) 6 provided on the lid 1a of the casing 1.

Example 2 92 parts by weight of metal Si powder having an average particle size of 0.9 μm and an average particle size of 2
Using a raw material having a mixing ratio of 8 parts by weight of μm TiN powder, mixing with a methanol in a pot mill, drying, and adding 9 parts by weight of a polyethylene wax, 150 parts by weight
The mixture was kneaded at 5 ° C. for 5 hours using a pressure kneader. Then, the mixture is crushed, and the casing 1 is subjected to the conditions of 150 ° C. and 1000 kg / cm ³ ,
It was molded with a mold having the shape of the elliptical gear 2, bearing 3, and shaft 4. After removing the wax content of the molded body, 1360
Heat treatment was carried out stepwise over a long period of time to ° C. Various members having a porosity of 11% were produced by such a method. here,
At this time, the rate of dimensional change from the molded body to the sintered body was as small as 0.2% or less, and a product excellent in dimensional accuracy was obtained. Then, it is incorporated into the flow meter of the actual machine, and the rotation speed is 500 rpm and the discharge flow rate is 2000
/ h, the fluid was subjected to an actual machine test of continuous operation for 100 hours with sulfuric acid 3% water. After the test was completed, the flow calculation was disassembled and the amount of wear and corrosion was measured. Table 2 shows the results. As a result, it was confirmed that the product of the present invention was superior in wear resistance and corrosion resistance as compared with the conventional material.

Example 3 Metal Si powder having an average particle size of 0.9 μm and SiC having an average particle size of 2 μm
After mixing and drying with a pot mill together with methanol using raw materials having various mixing ratios of powders, 5 to 13 parts by weight of polyethylene wax was added and kneaded at 150 ° C. for 5 hours using a pressure kneader. . And crush the mixture, 15
4th shape of the elliptical gear 2 under the condition of 0 ° C and 1000 kg / cm ³
Warm pressure molding was performed using the mold shown in the figure.

The molding die will be described. 51 is the dice, dice 51
In the center, there is a molding hole 51a which extends in the axial direction and penetrates
Is provided. The forming hole 51a has an elliptical cross-sectional shape, and a tooth shape 51b for forming the outer peripheral portion (teeth) of the flow meter rotor (elliptical gear) is formed on the peripheral wall of the die 5.
1 is formed to extend in the axial direction. 51c is the molding hole
A guide hole penetrating around the periphery of 51a, into which a guide pin described later is inserted and guided. Reference numeral 52 denotes a first pressing member. The first pressing member 52 includes a packing plate 53, a punch plate 54, and a punch 55. The packing plate 53, the punch plate 54, and the punch 55 are provided with guide holes 53a, 54a, and 55a, which extend in the axial direction, and into which core pins for forming a rotating shaft hole described later can be inserted. The punch 55 has an elliptical cross section similarly to the forming hole 51a, and has a tooth profile 55b meshing with the tooth profile 51b of the forming hole 51a on the outer peripheral wall. Packing plate 53, punch plate 54, punch
55 is fixed and integrated with bolts or the like (not shown) in a state where the guide holes 53a, 54a, and 55a are formed so as to communicate with each other to form the guide hole 52a. The first pressing member 52 is slidably held on the die 51 in a state where the punch 55 is inserted through the forming hole 51a of the die 51.

On the other hand, 56 is a second pressing member, which is a packing plate 57, a punch plate 58, a punch 59, a guide pin 60,
It comprises a core pin 61 for forming a rotary shaft hole and a core pin 62 for forming a mounting hole for a detected piece. Punch plate 5
8, through holes 58a and 59a are formed in the center of the punch 59 through which a core pin 61 for forming a rotary shaft hole is inserted.
A and 59a are provided around the core pin 62 for forming the detection piece mounting hole.
Are formed through holes 58b and 59b. Further, the guide plate 51c of the die 51 is formed in the punch plate 58.
Insertion hole 58c through which guide pin 60 is inserted to match
Are formed through. And the punch 59 is the punch
Similar to 55, the cross-sectional shape is elliptical, and the outer peripheral wall is formed with a tooth profile 59c that meshes with the tooth profile 51b of the forming hole 51a. The punch 59 and the punch plate 58 are fixed with bolts or the like (not shown) in a state where the core pins 61 and 62 are inserted into the insertion holes 58a, 59a, 58b and 59b, respectively. The guide pins 60 are fixed to the insertion holes 58c with bolts or the like (not shown).

As a result, the core pins 61 and 62 and the guide pin 60 are
It is positioned in its axial direction with respect to 58. In this positioned state, the core pin 61 for forming the rotary shaft hole is
The core pin 62 protrudes beyond the rotor length of the flow meter rotor to be formed from the tip surface of the punch 59, and the core pin 62 projects by a predetermined length necessary for burying the detection piece on the flow meter rotor end surface with respect to the punch 59 tip surface. State. Then, the integrated second pressing member having the above configuration is provided with a punch 59 in the forming hole 51a of the die 51 and a guide pin 60 in the guide hole 51c.
Is held so as to be able to be impulsive with respect to the die 51 in a state where is inserted.

After removing the wax component, the molded product molded by such a mold was subjected to a heat treatment in nitrogen gas at 1380 ° C. in a stepwise manner over a long period of time. Elliptical gears 2 having different porosity were manufactured by such a method. Here, the rate of dimensional change from the molded body to the sintered body at this time was as small as 0.2% or less, and a product excellent in dimensional accuracy was obtained. Then, it was installed in a flow meter of a real machine, and a real machine test was performed in which the rotation speed was 600 rpm, the discharge flow rate was 2100 / h, and the fluid was gasoline for 10,000 hours of continuous operation. After the test, the flow meter was disassembled, and the amount of wear and corrosion was measured. FIG. 3 shows the relationship between the porosity of the sintered body and the amount of wear and corrosion after 5000 hours of operation. It can be seen from this that when the porosity is 30% or more, the amount of wear and corrosion sharply increases, and when the porosity is 5% or less, the amount of wear and corrosion slightly increases. In particular, it was found that a porosity of 5 to 20 vol% was excellent in wear resistance and corrosion resistance.

Example 4 The pores of the elliptical gear 2 obtained in Example 2 were impregnated with fluorine oil and subjected to the same abrasion resistance and corrosion resistance test. And excellent in corrosion resistance. In the material of the present invention,
The oil in the pores provided a lubricating effect, and the reliability was greatly improved.

It has been confirmed that a similar effect can be obtained by impregnating with a solid lubricant, a fluororesin, grease or the like instead of the oil.

〔The invention's effect〕

By configuring the elliptical gear, casing, shaft, bearing, and the like of the flow meter with the ceramics of the present invention, it is possible to provide a flow meter excellent in unprecedented wear resistance, high-speed operation, and corrosion resistance.

[Brief description of the drawings]

FIG. 1-a is a longitudinal sectional view of the flow meter, and FIG.
2 is a schematic cross-sectional view of the ceramics of the present invention, FIG. 3 is a graph showing the relationship between the porosity and the wear amount of the elliptical gear member, and FIG. 4 is a mold. FIG. 2 is a cross-sectional structural view of a pressure molding machine using the above. 1 ... casing, 2 ... elliptical gear, 3 ... bearing, 4 ...
… Axis, 5… piece to be detected, 6… sensing element, 21… inorganic compound, 22… Si ₃ N ₄ , 23… pores, 24… attached fluid

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahisa Sobue 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Hiromi Koubara 832 Horiguchi Katsuta City, Ibaraki Prefecture Hitachi, Ltd. Inside the factory Katsuta factory (72) Inventor Takahiko Okochi 832, Horiguchi, Katsuta-shi, Ibaraki Pref. Inside Hitachi, Ltd. Katsuta factory (72) Inventor Hiroshi Hama Inside the factory (72) Inventor Masanori Fukushima 2-89-322 Asamachi, Tsurumi-ku, Yokohama, Kanagawa Prefecture (72) Inventor Toshio Oyagi 3-1-3-304, Fujisaki, Kawasaki-ku, Kawasaki-shi, Kanagawa 304 (72) Inventor Kyoji Imamura 1-1-19, Higashi-Tateishi, Katsushika-ku, Tokyo (56) References Japanese Utility Model Showa 62-24323 (JP, U) Japanese Utility Model Showa 62-24324 (JP, U) Japanese Utility Model Showa 62-24325 (J (P, U) Jpn. Sho. 62-24326 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 3/10

Claims (1)

(57) [Claims] 1. A flowmeter having a casing, an elliptical gear provided in the casing and rotating in accordance with a flow of a fluid to be measured, a rotating shaft for bearing the elliptical gear, and a bearing for supporting the rotating shaft. , An elliptical gear, a rotating shaft, and at least one of the bearings have an average particle size of 0.1 μm to 1 μm.
A molded body made of 00 μm SiC or TiN and metal Si powder,
Si whose average particle size obtained by nitriding is smaller than the SiC or TiN
₃ N ₄ by reaction bonded density 5 g / cm ³ or less, porosity 5～30Vol%
A flow meter comprising a porous Si ₃ N ₄ bonded SiC or TiN reaction sintered ceramic material.