JPH04347007A - Bearing structure of positive displacement flowmeter - Google Patents

Abstract

PURPOSE:To provide a constantly stable and reliable bearing without reducing measuring precision by preventing measuring liquid from being mixed in lubricating oil for the bearing during lubrication particularly when the flow of slurry liquid is measured. CONSTITUTION:Automatic alignment is performed by using an adjustable plate 7 in a housing 4, a bearing 6 having a projecting part 6a, and a thrust ring 8. Furthermore, a double seal composed of a V ring 13 and a cap seal 14 is used to prevent measuring liquid from being mixed in lubricating oil, which flows in lubricating oil passages 2a, 2b and a circuit comprising a bearing spiral channel 6c and an oil channel 8a so that the bearing 4 is subjected to forced lubrication.

Description

[Detailed description of the invention]

0001

[Technical field] The present invention relates to a bearing structure for a positive displacement flowmeter.
More specifically, the present invention relates to a bearing structure for a large volumetric flowmeter that is particularly suitable for measuring the flow rate of fluids containing slurry.

0002

BACKGROUND OF THE INVENTION As is well known, in a positive displacement flowmeter, a pair of rotors are driven to rotate within a measuring chamber by a fluid pressure difference of a fluid to be measured.
The flow rate is measured in proportion to the rotation of the rotor, with the volume of the fluid in the metering chamber removed by the rotor as a reference flow rate. Since the flowmeter rotor thus rotates in proportion to the flow rate, a positive displacement flowmeter is provided with a rotor shaft and a bearing that supports the rotor shaft. In medium to small volumetric flowmeters, the rotor shaft is often of the so-called fixed shaft type, with one end buried and fixed in the metering chamber, and the bearing fitted into the rotor. However, in large-sized positive displacement flowmeters, the rotor shaft is mainly inserted into the rotor and fixed, and a so-called shaft-rotating type is used, in which a bearing is attached to the main body casing.

[0003] Ball, roller, or plain bearings are used for the rotor shaft bearing.
These bearings are often selected depending on the metering fluid. In other words, ball bearings have low rotational friction torque, so they are suitable for measuring liquids with little slurry, but they are not suitable for liquids containing slurry or corrosive liquids, and are mainly used for such liquids. Carbon-based plain bearings are used.

In recent years, crude oil, COM (coal/oil mixed fuel), CWM (coal/water mixed fuel), etc. have been used as liquids containing slurry as boiler fuels in thermal power plants. Attempts have been made to measure the amount using a flow meter. For example, COM is a fuel oil made by adding a surfactant to crude oil and turning fine coal powder into a multiphase fluid. However, when measuring COM with a positive displacement flowmeter, slurry or particles may intervene between a pair of rotors. At this time, the rotor shaft applies a large compressive force to the bearing. Since this compressive force causes bending stress on the rotor shaft, the rotor shaft generates an uneven load on the bearing, which not only causes early friction of the bearing but also increases friction torque. Decrease flow accuracy.

[0005]

[Purpose] The present invention has been made in view of the above-mentioned problems. (1) Even if slurry is caught between the rotors and the rotor shaft is bent, the bearing will be able to respond to the deformation of the rotor shaft. (2) Preventing lubricating oil quality from deteriorating due to mixing of measuring liquid into lubricating oil; (3) Forcibly circulating lubricating oil without quality deterioration through bearings. This was done with the purpose of providing that.

[0006]

[Structure] In order to achieve the above objects, the present invention provides (1)
In a rotor bearing structure in a bearing box installed in a casing of a positive displacement flowmeter, there is provided a sealing means for liquid-sealing lubricating oil in the bearing box from the metering liquid, and forced lubrication for circulating the lubricating oil through the bearing. and a self-aligning means for rotating the bearing in response to minute rotation of the rotor shaft around the support point of the bearing; and (2) in (1) above, the sealing means is , with respect to an annular holding plate that is substantially fixed to the housing in a plane perpendicular to the rotor axis, one end surface of the holding plate on the measuring liquid side is fixed to the rotor shaft and the other end surface is fixed to the holding plate. The lubricating oil side is sandwiched and sealed by the holding plate, and the rotor shaft side is provided with an elastic seal that slides and seals.
), the forced circulation means includes a circulation oil passage that passes through the rotor shaft, opens on the outer circumferential surface of one end face of the bearing, and communicates with the lubricating oil; The bearing has a circulation flow path consisting of a spiral groove provided in the bearing, and an oil groove provided on the diameter of a thrust ring that passes through the spiral groove, is fixed to the rotor shaft, and slides on the other end surface of the bearing. and (4) in (1) above, the self-aligning means is fixed to the casing. The housing has a structure in which a flexible plate, a bearing, and a thrust ring are fitted in order into the annular bottom part of the housing, and the thrust ring is fixed to the rotor shaft, and the outer circumferential surface of the bearing is The central part of the housing is protruded, and the protrusion is in contact with the inner wall of the housing. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a structural diagram showing a side cross section of an embodiment of the bearing structure of a positive displacement flowmeter according to the present invention. In the figure, 1 is a rotor, 2 is a rotor shaft, 3 is a housing, and 4 is a housing, 5 is a lid, 6 is a bearing, 7 is a flexible plate, 8 is a thrust ring, 9 is a washer, 10 is a shaft nut, 11 is an adjustment spacer, 12 is a stop pin, 13 is a V ring, 14 is a cap 15 is a sliding metal fitting, 16 is an O-ring, 17 is a cap seal presser plate, 18 is a measuring chamber, and 19 is a bearing box.

In the figure, a rotor 1 (only a portion is shown) and a rotor shaft 2 fixed to the rotor 1 are disposed on the side of a measuring chamber 18 provided in a housing 3. . Also,
The bearing box 19 is a part whose exterior is made up of a part of the casing 3, a housing 4, and a lid 5.
is a cylindrical body fixed to the housing 3 at the flange 4a with bolts or the like, and has an annular bottom 4b. A flexible plate 7 and a bearing 6 are fitted inside the annular bottom portion 4b, and by providing a slight gap through an adjustment spacer 11 for the thrust ring, the bearing 6 is slid by the thrust ring 8. It's bordering on possible. The thrust ring 8 is fixed to the outer periphery of the end of the rotor shaft 2 by a key 8b, a washer 9, a shaft nut 10, and the like.

FIGS. 2(A) and 2(B) are diagrams for explaining the flexible plate structure. FIG. 2(A) is a plan view and FIG. 2(B) is a perspective view. Projections 7a, 7a' are provided at angles perpendicular to each other in the diametrical direction of the surface, and are freely rotated with respect to the surface in contact with the projections 7a, 7a'. The bearing 6 is a plain bearing made of carbon as a base material, and the sliding surface with the rotor shaft 2 is provided with a spiral groove 6c, and the center part of the outer peripheral surface has a large diameter that contacts the inner wall surface of the housing 4. The portion 6a and the outer portion of the large diameter portion 6a are formed with small diameter portions 6b, 6b having a smaller diameter than the large diameter portion 6a. The bearing 6 has a pin 12 embedded in a pin hole 6d.
is inserted into the keyway 4c to prevent the bearing 6 from rotating within the housing 4.

On the other hand, a ring-shaped sliding fitting 15 that is liquid-sealed with an O-ring 16 is fitted onto the rotor shaft 2 between the measuring chamber 18 and the bearing box 19 and fixed with screws. A V ring 13 is fitted onto the outer peripheral surface of the sliding fitting 15. The V ring 13 is provided with a ring-shaped tongue piece 13a, and the outer circumferential portion of the tongue piece 13a is connected to the measuring chamber 1 of the presser plate 17 fixed to the outer circumferential surface of the annular bottom portion 4b of the housing 4.
It is elastically pressed into contact with the surface on the 8 side for a liquid seal. Further, a cap seal 14 is pressed between the press plate 17 and the housing 4. The cap seal 14 is a sealing material that rotates and slides to seal the outer peripheral surface of the sliding fitting 15, and is made of an elastic body such as an O-ring whose sliding surface is coated with a resin material to increase friction resistance. . As described above, the measuring liquid in the measuring chamber 18 and the lubricating oil in the bearing box are doubly sealed by the V ring 13 and the cap seal 14 via the sliding fitting 15 and the presser plate 17.

Furthermore, an O-ring 1 is attached to the side of the housing 4.
A lid 5 sealed by a bearing box 6 is disposed, and the lid 5 forms an airtight container inside the bearing box 19, and lubricating oil for the bearing 6 is sealed in the airtight container. The rotor shaft 2 has lubricating oil passages 2 a and 2 b that open at the end face of the rotor shaft 2 and pass through the shaft to reach the vicinity of the end face of the bearing 6 . The opening of the lubricating oil passage 2a is located at a position where lubricating oil can be introduced, and is filled with lubricating oil. The opening of the lubricating oil passage 2b communicates with a spiral groove 6c of the bearing, and the other end of the spiral groove 6c communicates with an oil groove 8a provided on the diameter of the thrust ring. It is open inward.

[0012] When the rotor rotates during flow rate measurement,
The lubricating oil in the bearing box 19 is sealed between the V-ring 13, the cap seal 14, the sliding fitting 15, and the holding plate 17, so that the lubricating oil is not mixed with the metering liquid and is transferred to the bearing. Due to the infusion action caused by the rotation of the spiral groove 6c of 6, the spiral groove 6
c and oil groove 8a.

Even if foreign matter such as slurry gets caught between the rotors 1.1 and causes bending stress on the rotor shaft 2, the bearing 6 is self-aligned by the flexible plate 7 and the large diameter portion 6a. Bearing 6
The rotor 1.1 continues to rotate smoothly without any unbalanced load acting on the shaft 2 and the shaft 2.

[0014]

[Effect] As is clear from the above description, according to the present invention, a self-aligning mechanism consisting of a flexible plate disposed in a housing, a bearing, and a thrust ring is used to improve Even when measuring mixed fuel, etc., it is automatically adjusted and lubrication is performed satisfactorily, making it possible to measure the flow rate with high precision.Furthermore, the lubricating oil and the measuring liquid are completely sealed, so that the measuring liquid does not mix with the lubricating oil. The lubricating oil is forced to circulate through a circulation path consisting of a lubricating oil path drilled in the rotor shaft, a spiral groove in the bearing, and an oil groove in the thrust ring, which also shortens the life of the bearing. Since the flowmeter is extended, a highly reliable positive displacement flowmeter can be provided.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing a side cross section of an embodiment of a bearing structure for a positive displacement flowmeter according to the present invention.

FIG. 2 is a diagram for explaining a flexible plate structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Rotor, 2...Rotor shaft, 3...Casing, 4...Housing, 5...Lid, 6...Bearing, 7...Flexible plate, 8...Thrust ring, 13...V ring, 14...Cap seal, 15 ...Sliding metal fitting, 17...Cap seal presser plate, 18...Measuring chamber,
19...Bearing box.

Claims (4)

[Claims] 1. A rotor bearing structure in a bearing box installed in a casing of a positive displacement flowmeter, comprising: a sealing means for liquid-sealing lubricating oil in the bearing box from a metered liquid; A bearing structure for a positive displacement flowmeter characterized by comprising: a forced lubrication means that circulates the rotor shaft; and a self-aligning means that rotates the bearing in response to minute rotations of a rotor shaft around a support point of the bearing. 2. The self-aligning means rotates the thrust ring by sequentially fitting and inserting a flexible plate, a bearing, and a thrust ring into the annular bottom part of the housing, which is fixed to the housing and has an annular bottom part. 2. The bearing structure for a positive displacement flowmeter according to claim 1, wherein the bearing has a structure that is fixed to the child shaft, and a central portion of the outer circumferential surface of the bearing is protruded, and the protrusion is in contact with an inner wall of the housing. 3. The sealing means is an annular holding plate that is substantially fixed to the casing in a plane perpendicular to the rotor axis, and one end surface of the holding plate on the measuring liquid side is connected to the rotor axis. A claim characterized in that the rotor has an elastic seal plate which is fixed and whose other end surface slides on the presser plate, and the lubricating oil side is clamped and sealed by the presser plate and has an elastic seal that slides and seals on the rotor shaft side. Bearing structure of the positive displacement flowmeter according to item 1. 4. The forced circulation means passes through the rotor shaft,
a circulating oil passage that opens on the outer peripheral surface of one end face of the bearing and communicates with lubricating oil; a spiral groove that communicates with the circulating oil passage and is provided on the sliding surface of the bearing; and a spiral groove that passes through the spiral groove; It has a circulation flow path consisting of an oil groove provided on the diameter of a thrust ring that is fixed to the rotor shaft and slides on the other end surface side of the bearing,
2. A bearing structure for a positive displacement flowmeter according to claim 1, wherein the lubricating oil is circulated through the circulation channel by pressure in a spiral groove generated as the rotor shaft rotates.