JPS62140022A - Flowmeter - Google Patents

Abstract

PURPOSE:To enable the accurate measurement of a flow amount while reducing force for rotating a blade wheel, by providing spiral grooves to at least either one of the end surface of the rotary shaft of the blade wheel and the bearing surface sliding with said end surface to each other. CONSTITUTION:A main body 1 is partitioned by a partition wall 4 between the inflow port 2 and outflow port 3 thereof and a circular fluid passage 5 is formed in the partition wall 4 and a case 7 having a resin plate 8 mounted on the bottom surface thereof is engaged with the circular hole 15 directly above the passage 5 in a hermetically sealed state. A blade wheel 13 consists of a blade 14 and a shaft end member 16 and magnets 17 are embedded in the member 16 and spiral grooves 19 are formed on the end surface of said member 16. A Hall element 21 mounted on the plate 8 detects the magnetism of the magnet 17 to determine the state of rotation of the wheel 13 and the signal detected by said element 21 is led to the outside. By this method, the wheel 13 rotates when a fluid to be metered flows through the main body 1 and the spiral surface rotates in the direction shown by an arrow A. At this time, a force for allowing a fluid to move from the outer peripheral side of the grooves 19 toward the center thereof is generated and a pressure difference is generated between the wheel 13 and the plate 9 to form a fluid film. The wheel 13 rotates with low sliding resistance.

Description

[Detailed description of the invention] [Object of the invention] "Industrial application field" The present invention is an impeller-type flow rate system that can measure the flow rate of all kinds of fluids such as water vapor and gas with high precision and stably over a long period of time. It is related to the meter.

``Prior Art'' FIG. 5 shows a conventional small-capacity impeller-type flowmeter water meter. Water flowing in from the inlet 2 passes through the filter 5
2, enters the inlet side 1a of the main body 1 partitioned by the partition wall 4, enters the case 54 through the hole 55 provided in the case 54 of the measuring unit 53, which is fitted and fixed in the main body 1, and enters the case 54 through the hole 56 of the case 54 to the exit of the partition wall 4. It exits to the side 1b and flows out from the outlet 3. The impeller 66 is rotated by the water flowing in and out of the case 54, and the rotating shaft 57 to which the impeller 36 is fixed is rotated. The lower end of the rotating shaft 57 has a conical shape and is supported by a pivot bearing 581 screwed into the case 54. A conical shaft end provided at the upper end is supported by a pivot bearing 51 that is sealed and protrudes into the instrument box 59 and screwed into the instrument box 59. Therefore, impeller 5
6 is guided to the instrument box 59 by the rotating shaft 57, and the rotation of the instrument box 5
9, a gear train 64 interlocked with a gear 65 fixed to a rotating shaft 57 rotates, and each shaft of the gear train provided with a pointer 63 passing through the scale plate 62 and extending upward rotates to move the pointer 63. Rotate. Corresponding to the pointer 63, each digit of the water amount is displayed on the scale plate 62 as an analog amount. A glass 66 seals the instrument box 59.

``Problems to be solved by the inventionj'' The flowmeter needs to have a small starting torque to drive the impeller 36 with a small flow rate and detect the flow rate.
It is necessary that the rotational speed of 6 is accurately proportional to the flow rate. However, in the above-mentioned flowmeter, the shaft sealing device 61 needs to be complete, and if water leaks from the shaft sealing device 61, the scale plate 62 becomes difficult to see and the gears and pointer 63 move in the liquid, increasing resistance. Therefore, as a countermeasure, the shaft sealing device 61
The frictional resistance increases. Furthermore, the frictional resistance caused by the gear train in the instrument box 59 is large, and the speed changes of the gears are also large, so the frictional resistance also fluctuates widely, leading to large measurement errors.

The fluid measured by a flowmeter is not limited to fresh water, so iron rust,
It may contain sand or handle seawater, etc. Therefore, the lower pivot bearing 58 must not wear out or corrode under such an environment. If leakage occurs in the shaft sealing device 61, it may result in poor or impossible measurement.

It is necessary that a flow meter be easy to handle, but in the conventional example described above, when used as a water dispenser, the meter must be read by bending over, making it difficult to increase its handling.

Other types of impeller flow meters also have bearings that support the impeller placed in the liquid, and the impeller shaft is sealed, but they have the same problems as above.

It is an object of the present invention to solve the problems associated with impeller type flowmeters, to provide a durable flowmeter with less measurement error.

[Structure of the invention]

``Means for Solving the Problems'' The first aspect of the present invention includes an impeller which is rotatably driven by the fluid flowing through the main body, which is provided with an inlet and an outlet for the fluid to be metered, and the number of revolutions of the impeller is In a flowmeter that measures the flow rate based on the rotation of the impeller, dynamic pressure is generated in the center of the impeller on at least one of the end face of the rotating shaft of the impeller and the bearing face placed opposite this end face. This is an impeller-type flowmeter with a unidirectional spiral groove.

Further, the second invention provides a flowmeter that includes an impeller rotationally driven by the fluid flowing through the main body, which has an inlet and an outlet for the fluid to be measured, and measures the flow rate based on the number of rotations of the impeller. , a unidirectional spiral groove is formed on at least one of the end face of the rotating shaft of the impeller and a bearing face disposed opposite to this end face so that dynamic pressure is generated in the center by rotation of the impeller; This is an impeller-type flowmeter in which a permanent magnet is fixed to the impeller, and the rotation of the impeller is detected by a Hall element provided in the main body.

"Operation" When the impeller rotates due to the normal flow of fluid, the central part is rotated by the action of the unidirectional spiral groove formed on at least one of the shaft end surface of the impeller or the bearing surface on the main body side facing this. That is, positive dynamic pressure is generated in the center of the bearing, and the impeller and bearing slide smoothly through the fluid film. Here, in order to effectively generate dynamic pressure, it is preferable to use ceramics (SiC, Si3N4.AJ20x, etc.) as the member of the surface forming the spiral groove.

In the second invention, the rotation of the permanent magnet fixed to the impeller can be detected by the Hall element.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view, and the main body 1 has an inlet 2 and an outlet 3.
A partition wall 4 partitions the space between the two, and a circular fluid passage 5 is formed in the partition wall 4. Circular hole 1 directly above passage 5 of main body 1
A case 7 having a resin plate 8 on the bottom is hermetically fitted into the case 5.

FIG. 2 is a partially enlarged longitudinal section of FIG. 1, and shows that a ceramic bearing plate 9 is attached to the lower part of the resin plate 8, and the sliding surface 9a of the bearing plate 9 has a smooth mirror finish. A ring-shaped magnet 10 is embedded therein, and a recess 12 into which a small ball 11 is to be inserted is formed at a position corresponding to the axis. The impeller 13 is composed of blades 14, a main shaft 115, and a shaft end member 16, and a magnet 17 is embedded in the shaft end member 16 in order to magnetically detect the rotation of the impeller 13. .

Furthermore, the shaft end member 16 of the main shaft 115 of the impeller that faces this bearing plate 9 is made of ceramics, and its end surface 18 is mirror-finished as shown in FIG. is forming. Further, a ring-shaped magnet 20 is similarly embedded in this shaft end member 16, and this magnet 20 attracts a magnet 10 embedded in the bearing plate 9 to prevent the impeller 13 from shifting from a predetermined position. There is. The aforementioned magnet 17 is buried in the surface where the spiral groove 19 is formed, and the Hall element 21 attached to the resin plate 8 detects the magnetism of the magnet 17 to determine the rotational state of the impeller 13. The signal detected by the Hall element 21 is guided to the outside of the flowmeter by a cable.

The impeller 13 rotates in the direction of arrow A due to the normal flow of fluid.

As mentioned above, the shaft end member 16 is made of ceramics, and its sliding surface is finished with a smooth mirror finish.It also depends on the properties of the fluid present on the bearing surface, but if it is a liquid, it will be 5 to 5 mm.
A plurality of spiral grooves 19 with a groove depth of 0 μm are formed. These spiral grooves 19 are all impellers 13
It is centered on the main axis 115 of the central part 1.
The entire circumference of the groove 21 is machined to the same depth as the spiral groove 19. Furthermore, a ring-shaped magnet 20 is attached to the center portion 121.
It looks slightly receded. 12 is a recessed portion.

When the fluid to be measured flows inside the main body 1, the impeller 13 rotates and the spiral surface rotates in the direction of arrow A. At this time, the fluid is moved from the outer circumferential side of the spiral groove 19 toward the center. A force is generated, and as a result, a large pressure is generated between the impeller 13 and the bearing plate 9, and a fluid film is formed. The impeller 13 rotates with extremely small sliding resistance.

In the embodiment, the impeller 13 is brought into close contact with the bearing plate 9 by the makufutsu 1-10.20, but this is not necessarily necessary; for example, in FIG. If it is supported from the main body 1, it can be prevented from falling off, so there is no need for a magnet. In addition, the bearing plate 9
In more detail, the shaft end member 16 is made of a ceramic plate with a thickness of about 2 cm, and the back of the recess 12 that accommodates the small ball 11 is made convex for reinforcement to facilitate positioning. There is.

Since it is desirable that the sliding surface be extremely smooth, it is finished to a mirror surface by lapping, and waviness on the same surface is also minimized.

Then, either side is fine, but a wound mask with a spiral groove 19 (in the shape of a groove that does not carve) is placed on one side, and grooves of about 3 to 50 μm from the mirror surface are created by shot blasting. It is used to process.

The ceramics used are SiO, AJ203°Si
A wide range of materials such as 3N4 can be applied. Further, even if the spiral groove 19 is formed on the sliding surface 9a of the bearing plate 9, the same effect can be obtained.

For an impeller type flowmeter, it can be said that the root performance with a small measurable minimum flow rate is good, but in order to reduce this minimum flow rate, the sliding part when the impeller 16 is stationary Is it desirable to reduce the solid contact area on the bearing plate? It is also effective to form spiral grooves that generate dynamic pressure on both sliding surfaces of the shaft end member 16, or to form radial grooves on one surface. FIG. 4 is a front view of the sliding surface of the bearing plate 9 which has been processed with radial grooves, 22 is the sliding surface finished to a mirror finish, and 23 is the facing surface by shot blasting. A radial groove machined with a groove depth shallower than the spiral groove of 1 to 3 μm is effective.

10 is a ring-shaped magnet, and 12 is a recess in which the small ball 11 is accommodated. Note that the small balls 11 are made of ceramics or metal.

The number of rotations is counted by guiding the pulses generated by the Hall element 21 when the magnet 17 passes the position of the Hall element 21 to a counting device (not shown).

In addition to the above-mentioned embodiments, it is also possible to use the rotor and bearing part of a turbine-type flowmeter, and when used in this turbine-type flowmeter, the shaft end face on the downstream side of the rotor and the fixed side opposite thereto. SiC, 5ixN4. with a spiral groove formed on at least one of the bearing surfaces of the SiC, 5ixN4. Dynamic pressure may be generated by rotation of the rotor using a ceramic material such as A2203.

Although the embodiment uses a Hall element and a magnet to detect the number of rotations, the number of rotations may also be detected by a capacitive type, an inductive type, or the like.

〔Effect of the invention〕

The present invention relates to a flow meter that includes an impeller that is rotatably driven by a fluid flowing through a main body that has an inlet and an outlet for the fluid to be measured, and that measures the flow rate based on the number of rotations of the impeller. Since a spiral groove is formed on at least one of the end faces and the bearing surface that slides against each other in a direction that generates dynamic pressure in the center by the rotation of the impeller, the force required to rotate the impeller is extremely small. Flow rate can be measured accurately.

In the second invention, a magnet is embedded in the impeller and changes in the magnetic field caused by the rotation of the impeller are detected by a Hall element. Since the end portion and the bearing portion slide through a fluid film, vibrations are small and accurate measurement is possible.

Furthermore, since the sliding portion can be made of ceramics, it has excellent durability regardless of the fluid used. Also,
A magnet can be attached to the center of the sliding surface of the bearing to provide adsorption or repulsion as necessary.In this way, the surface of the magnet is protected by the sliding surface, so iron rust will not occur. The amount of adhesion of magnetic substances, such as

Furthermore, if the fluid inside the main body flows in the opposite direction, the impeller will rotate in the opposite direction, but in the flow meter of the present invention, when the impeller rotates in the opposite direction, it will slide due to the action of the spiral groove. The fluid present on the surface is discharged to the outside world, which acts as a force to attract the impeller to the bearing, and has the effect of suppressing reverse rotation of the impeller. Therefore, in a flowmeter that magnetically detects the rotation of an impeller like the second invention, there is an advantage that the error is reduced.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, FIG. 3 is an explanatory diagram of the shape of the spiral groove, and FIG. FIG. 5 is a front view of a sliding part in another embodiment of the present invention, and FIG. 5 is a vertical cross-sectional view of a conventional example.
・Separation plate 5・・Passage 7・・Case 8・・Resin board 9
・・Bearing plate 9a・・Sliding surface 1°・・Ring magnet 11・・Small ball 12・・Concave part 16・・impeller
14. Wing 15. Circular hole 16. Shaft end member 17.
・Magnet 18-・End face No. 19・Spiral groove 2
0...Ring-shaped magnet 21--Hall element 22
...Mirror finish surface 23...Shot finish surface 115
...Main axis.

Claims (2)

[Claims] (1) In a flowmeter that is equipped with an impeller that is rotationally driven by the fluid flowing through the main body that has an inlet and an outlet for the fluid to be measured, and that measures the flow rate based on the number of rotations of the impeller, the rotation axis of the impeller A unidirectional spiral groove is formed on at least one of the end face and the bearing surface disposed opposite the end face so that dynamic pressure is generated in the center by rotation of the impeller. Characteristic impeller type flowmeter. (2) In a flowmeter that is equipped with an impeller that is rotationally driven by the fluid flowing through the main body that has an inlet and an outlet for the fluid to be measured, and that measures the flow rate based on the number of rotations of the impeller, the rotation axis of the impeller A unidirectional spiral groove is formed on at least one of the end face and a bearing surface disposed opposite to the end face so that dynamic pressure is generated in the center by the rotation of the impeller. A permanent magnet is fixed to the impeller,
An impeller-type flowmeter characterized in that the rotation of the impeller is detected by a Hall element provided in the main body.