JPS61114130A - Capacity type flow meter - Google Patents

Abstract

PURPOSE:To discharge abrasive fine particles, which are produced at the sliding part of a rotating shaft, from the system of a tube flow without mixing them with pure water to be measured by linking outlets for discharging abrasive fine particles with a bearing part and connecting them to a discharge pipe outside a case. CONSTITUTION:The outlets 8 communicating with slide surfaces between bearings 7 of the case 1 and sliding surfaces of shafts 5 and 6 are provided and connected to communication discharging pipes 9, and led to a container 10. When the pressure in the container 10 is set a little bit lower than the pressure in a measuring chamber 1 through a pressure valve 12, fine particles produced by the sliding of the bearings 7 on the sliding surfaces are discharged to the container 10 through the discharging pipes 9 without moving to the measuring chamber. At this time, the flow rate is controlled by a control valve 12 through a flow meter 11 so that the amount of pure water flowing out to the discharge pipes 9 is not excessive.

Description

[Detailed Description of the Invention] Cleaning is an essential step in the semiconductor manufacturing process.
Extremely pure water is required, and since conductive wires with a fine line width of less than a micrometer must be drawn on the substrate of highly integrated semiconductors, this line width is reduced by a washing process that is repeated many times before and after each process. If the damage is larger than that, the conductor will be severed.

Therefore, ultra-pure water is required to have a high degree of purity, such as the number of microparticles of 0.1 E chlorine in one cubic starch, and the production of ultrapure water is carried out using a leakage device that uses a reverse osmosis membrane made of polymeric substances. It will be done. It is important to prevent the generation and contamination of impurities such as fine particles and oil in ultrapure water washing equipment. Highly accurate flow control is performed in the semiconductor washing process, and positive displacement flowmeters are the only applicable flowmeters that can measure pure water with high precision. However, positive displacement flowmeters have a mechanical structure in which the rotating body that performs the measuring function rotates while maintaining a minute clearance within the measuring chamber, so the rotating parts are subject to wear due to contact friction, which generates fine particles. For example, fine carbon particles due to contact between solids on the sliding surfaces of a stainless steel shaft and a carbon bearing mix into the pure water of the fluid to be measured.
During cleaning, semiconductors will be soaked in a pot. The cleaning of delicate and precise semiconductors requires a higher degree of control of minute and highly accurate flow rates, and in order to meet this requirement, it is necessary to An instrument with small instrumental error is desirable. That is, by reducing the speed of the rotating element, the dynamic load on the bearing portion is significantly reduced, so that the wear caused by the friction is reduced. However, since the pure water in the pipe flow is a fluid with extremely low lubricity, it is thought that fine particles will naturally be generated due to solid contact at the bearing part. Oval gear type flowmeters are highly accurate flowmeters due to the meshing of the teeth of the rotor, but the tooth surfaces where the non-circular gears interlock and mesh with each other have a load that is much higher than the surface pressure load of the bearings. Since the friction is said to be low, the generation of fine particles is small, but on the other hand, the rate of generation of wear particles due to contact sliding of the bearing is high. The cocoon-shaped rotor of the Roots-type flowmeter rotates without contact, but the t-coat interlocking gear that interlocks the gills rotates in a gear pile that communicates with the metering chamber, so the t-coat rotor is caused by the meshing between the interlocking gears. Fine powder particles are mixed into pure water.

An object of the present invention is to eliminate fine abrasion particles generated in the bearing portion of the rotor of a positive displacement flowmeter out of the pipe flow system without being mixed into the pure water being measured.

An example will be explained.

FIG. 1 is a side view of an elliptical gear type flowmeter according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A' in FIG. Rotors 3 and 4 are installed in the metering chamber 2 of the flowmeter case 1.
are integrally formed with each rotor, respectively.Rotating shafts 5 and 6
is rotatably housed by a bearing 7. In FIG. 2, a slot 8 is provided on the opposite side of the measuring chamber at the sliding surface of the shaft 5 in contact with the inner surface of the bearing 7 of the case 1, and is connected to the communication discharge pipe 9.
11 is a flow meter that detects the flow rate.

Similarly, a groove hole 8 is provided in each bearing 7 to communicate with the communication discharge v9 and lead to the container 10. The slot 8 and the communicating discharge pipe 9 have small diameters to minimize the necessary flow rate. Discharge pipe 9
A control valve 18 can be installed in the g10 to control the miscarriage, and a pressure valve 12 can be installed in the g10 to correspond to the pressure of the pipe flow. The pressure is maintained at a level slightly lower than that in the measuring chamber 1, and the pressure is introduced into the container through the communicating discharge pipe 9. The fine particles generated on the bearing sliding surface are pushed out by the fluid (pure water) flowing out from the measuring chamber 2 into the discharge pipe 9 at a slightly lower pressure and are discharged into the volume @g10.The fine particles generated on the bearing sliding surface are discharged into the measuring chamber. It is possible to control the flow rate while maintaining the purity of the pure water by appropriately adjusting it with the control valve 18 so that it does not move and the amount of pure water flowing into the discharge pipe 9 does not become excessive.

Next, FIG. 3 of the second embodiment shows an elliptical gear type flowmeter in which a fixed shaft is provided with a slot, and the shafts 51 and 6 are fixed in the case 1. The rotors 3 and 4 are housed in the rotors 3 and 4 in meshing engagement with each other so as to be rotatable through bearings 7°. The rotor 3. When rotating, the inner surface of bearing 7□ and shaft 5
1 slides on the contact surface hone. The fine particles generated on the sliding surface are removed from the slot 8 provided in the center of the sliding surface of the shaft 51. and a discharge pipe 9 which communicates with this and is maintained at a lower pressure than the inside of the metering chamber.
This prevents the pure water in the measuring chamber from flowing from one side to the other and being discharged into the container 111 and being mixed in during management.

FIG. 4 shows an example of a Roots type flowmeter using a wear-out fine particle discharge mechanism. The Roots rotors 32 and 42 in the metering chamber 1 are connected to the interlocking gear 13 in the interlocking gear receiving chamber 15, respectively.
and 14 and integrally formed with the shafts 52 and 62, and bearings 72 and 7. It is rotatably stored. Bearing 72
The side slot 82 communicates with the discharge pipe 92 and is connected to the gear housing chamber 150.
The conduit hole 83 provided in the section communicates with the discharge pipe 92 and the container via the valve]1□.
Guided to 02. By keeping the pressure in the slot 82 and the gear storage chamber 15 lower than that in the metering chamber 2, abrasion particles generated by the rotation of the bearing and the interlocking gear are discharged into the container 102.

FIG. 5 shows an embodiment in which the non-circular rotating body of the elliptical gear type flowmeter is integrally formed with the interlocking elliptical gear on the same axis, and the fluid contaminated with foreign matter is discharged through a discharge conduit.

Non-circular rotors 33 and 4 engaging each other in the metering chamber 2
3 are integrally constructed with interlocking elliptical gears 16 and 17 on shafts 53 and 63, respectively. Elliptical gears 16 and 17 are non-circular rotors or elliptical gears 33 and 4. Set to the same elliptical pitch line as t and make it an interlocking gear to accelerate and decelerate while engaging and interlocking. Since the non-circular rotating bodies 33 and 43 rotate without contacting each other with a small gap between them, no abrasion particles are generated in the measuring chamber, and bearings 7. A gear storage chamber 15 is provided with a slot 83 at its outer end and is led to the container 10 through a communication discharge pipe 9, and accommodates interlocking gears 16 and 17 integrally formed at the end of the shaft supported by a bearing 74. slot 8
4 is led out of the case through the communication discharge pipe 9, so that fine particles of abrasion generated at the bearings and the meshing parts of the interlocking gears are discharged out of the system without being mixed into the pipe flow.

In the mechanism shown in Fig. 5, it is also possible to create a pump structure by connecting one shaft to a power source and driving it, and by installing pressure gauges on the inlet and outlet sides of the main body, the pressure difference can be determined. , and also includes applications in which the accurate flow rate of the pipe flow to be pumped is measured by sensing the flow rate discharged from the discharge conduit and measuring the rotational speed of the rotor of the main body.

FIG. 6 shows an embodiment in which the elliptical gear rotors 34 and 44 are rotatably housed in the measuring chamber 2 of the case 1, with their shaft holes fitting into the fixed shafts 54 and 64, respectively.

The bearing sliding part torch has a minute gap, and each of the shafts 54 and 64 has a hollow slot 84 connected to the communication pipe 9 and drained to the outside via the pressure regulating valve 11. The pressure inside the communication pipe is regulated by a valve to a pressure slightly lower than the pressure inside the metering chamber. In the figure, a part of the fluid to be measured (pure water) in the measurement chamber is pushed out from the bearing part T to the bearing part due to the pressure difference.
Wear particles generated on the sliding surface are discharged from the left end of the shaft through the slot 84 into the system.

FIG. 7 shows shafts 56 and 66 which are fixed upright in the case 1 and a short shaft 5. ,6. are integrally constructed, and the short shaft is supported by a pivot. Slot holes 84 are provided in the short axes 55 and 65. Each slot is connected to a communicating pipe 91, and the pressure is maintained lower than that in the metering chamber 2 by a pressure regulating valve. Fluid migrates through slots 84 and 8. It is discharged to the outside through the communication pipe 9.

As semiconductor manufacturing technology becomes more sophisticated, precision in flow control becomes increasingly important in the cleaning process, and along with the high precision of the flow meter itself, attached mechanisms such as devices that adjust and measure the flow of branched flows containing discharged impurities are also required. Included in the present invention,
It also includes applications such as the structure described above to maintain and enhance the impurity removal mechanism and flow control function for maintaining the purity of ultrapure water as the fluid to be measured. The present invention also includes applications in which the principles of the present invention are used in a structure sealed with a thrust bearing or in a mechanical seal structure.

[Brief explanation of the drawing]

Fig. 1 is a partially vertical side view showing an embodiment of the present invention in which a discharge communication pipe is provided in the bearing part of an elliptical gear type flowmeter, Fig. 2 is a sectional view taken along the line A-A' in Fig. 1, and Fig. 3 The figure is a sectional view showing another embodiment in which a slotted hole is installed in the fixed shaft of an elliptical gear type flowmeter and foreign matter is discharged through a discharge communication pipe. Figure 4 is a sectional view showing another embodiment in which a slotted hole is installed in the fixed shaft of an elliptical gear type flowmeter. Fig. 5 is a longitudinal sectional front view showing an example of a configuration in which foreign matter is discharged through a communicating pipe, and Fig. 5 is a longitudinal sectional front view showing an example of a configuration in which foreign matter is discharged through a communicating pipe. 6th longitudinal sectional front view of an embodiment configured to discharge
The figure is a longitudinal sectional front view of an embodiment in which an elliptical gear is fitted to a fixed shaft and a slot is provided in the shaft, and Figure 7 is a method for removing worn foreign matter from an elliptical gear type flowmeter in which a slot is provided in an upright fixed shaft. FIG. 3 is a cross-sectional plan view of the embodiment. 1... Case 2 Measuring chamber 3 and 4... Elliptical gear rotor 32 and 4□ Roots type rotor 5 and 6... Shaft
7. Bearing 8. Slot 9. Communication discharge pipe 10. Container
11.Flow meter 12..Pressure m regulating valve 13 and 14..
Interlocking gear 15...gear l! 11 16 and 17 ・
Interlocking elliptical gear 18...Control valve Fig. 3 Fig. A Fig. 6 Fig. 7 December 5, 1980 1. Indication of the incident Patent application No. 1987-235897 2. Name of the invention Positive displacement flow meter 3 Amendment Relationship with the case of the person who filed the patent application Patent Applicant Shun Kita Shun 4 Agents 1 Gu 1 5 Amendments to the Subject of Sleeve Correction The following amendments are made on page 7, line 4 of the inside diameter. Furthermore, by coating the inner wall of the measuring chamber 2 and the surfaces of the non-circular rotors 3 and 4 with a plating or synthetic resin coating, such as a fluorine-based resin fine ceramic coating, the rust prevention effect and metal ion outflow can be improved. The synthetic resin coating on the rotor rotates without contact, so it is not subject to wear, and has high electrical insulation even if minute particles peel off or flow out. Therefore, there is no risk of the printed circuit board being damaged during cleaning.It has the same effect when configured as a flowmeter or pump device for food products, etc. ! 'l'dl Applicant Michitoshi Kitano Procedural Amendment (Voluntary) January 1980/F Day

Claims (1)

[Claims] In a positive displacement flowmeter, a pair of non-circular rotors that engage and rotate with each other due to the flow of the fluid to be measured rotate within a measuring chamber.
The flow meter is equipped with a bearing that obstructs the rotation of the rotor within the case of the flowmeter, and a groove in the bearing sliding part is provided to communicate and discharge fine particles of abrasion generated in the bearing sliding part to the outside of the case. A positive displacement flow meter connected to the chamber and the opposite end or intermediate part thereof.