JPS61213632A - Volumetric flow meter - Google Patents

Abstract

PURPOSE:To obtain an inexpensive flow meter with high precision by reducing the effect of dynamic pressure which exerts an adverse influence upon a noncircular rotator, providing a fluid lubricating flow and reducing the friction of a bearing, and eliminating completely the amount of a leak which is by-passed between an inner and an outer cylinder. CONSTITUTION:Rotational frequencies of noncircular gears 21 and 22 rotated by fluid which reaches a measurement chamber through intakes 11 and 25 and flows out of an outlet 12 are counted to measure the flow rate. At this time. the mean pressure of inflow pressure and outflow pressure operates on the outside of the end surface of the inner cylinder 20 through a duct port 41 open in an upper lid 40 from above and through the intake 25 from below, so a pressure difference from outside the inner cylinder to the inside is generated at the bearing part and causes a flow for bearing lubrication to reduce the friction of the bearing, thereby improving the precision. Further, liquid is stored in a liquid reservoir 26 hollowed in the end surface of the rotator to prevent the early abrasion of the bearing. Liquid sealing between the inner and outer cylinders, on the other hand, is attained completely by packings 51 and 52, etc., and liquid with outflow pressure fills the gap 60, so pressure balance is stabi lized and the influence of piping stress is hardly exerted.

Description

[Detailed description of the invention] upper The present invention relates to a positive displacement flowmeter.

Figure 3 is a diagram for explaining an example of a conventional integrated positive displacement flowmeter. In the figure, 1 is a positive displacement flowmeter body having an inlet 2 and an outlet 3, A pair of non-circular gears 5 and 6 are rotatably disposed in the chamber 4, and as is well known, the cumulative flow rate of the fluid flowing in the direction of the arrow within the flow meter body 1 is determined by the number of rotations of the gears 5 or 6. is being measured. In the integrated flowmeter as described above, the metering chamber 4 is deformed due to the pressure difference between the metered liquid and the outside air pressure. Measuring chamber 4 and rotor 85.
The amount of leakage from the gap between 6 and 6 increases in proportion to the pressure difference, so for flowmeters used in transactions, a separate type flowmeter is used in which the measuring chamber is housed within the outer casing to eliminate pressure effects. .

FIG. 4 is a diagram for explaining an example of the separate flowmeter. In the figure, 10 is an outer cylinder having an inlet 11 and an outlet 12 for the fluid to be measured, and 20 is a non-circular gear 21 (and 22). )
The inner cylinder 20 has an inflow port of the same shape and size corresponding to the inflow and outflow ports 11 and 12 of the outer cylinder, respectively, on the side surface of the inner cylinder 20. Outflow window 29 is open. Further, a pressure guiding hole 251 is also bored on the inlet side of the bottom surface. 40 is an inner cylinder lid, and the inner cylinder lid 40 has a pressure guiding hole 41.
1 is bored and is concentrically and integrally fastened to the inner cylinder 20 with bolts (not shown) or the like. 23 (and 24) is a rotating shaft of the non-circular gear which is supported by the inner cylinder 20 and the inner cylinder cover 40. The integrated inner cylinder part is formed between the inner cylinder outer surface 27 and the outer cylinder inner surface 13, and is fitted into the outer cylinder with dimensions that minimize the gap, and is fitted with a sealing material such as a ``0'' ring. The upper part of the inner cylinder is fluid-tightly secured to the liquid chamber by means of bolts or the like (not shown).

I'm going to do it In the conventional separate type flowmeter as described above.

Although it is possible to prevent the amount of leakage caused by deformation due to the pressure difference between the outside and outside of the measuring chamber, it is not possible to prevent the amount of leakage as an error factor that is bypassed from the minute gap between the inner and outer cylinders due to the difference in pressure between the inflow and outflow.

Pressure conduction hole 251.4, which is also a factor that affects the amount of leakage
11 also has an opening area small enough to introduce static pressure. In order to reduce the amount of leakage, it is necessary to increase the machining accuracy and reduce the gap, but on the other hand, there is a problem in that it is easily affected by piping stress. Furthermore, since the inflowing fluid directly collides with the rotor, it acts as dynamic pressure, which adds a bending moment to the shaft, increasing bearing friction and causing problems such as the need to increase the shaft diameter to strengthen shaft rigidity. there were.

The present invention has been made for the purpose of eliminating the above-mentioned problems.

Figure 1 is a side sectional view for explaining one embodiment of the positive displacement flowmeter according to the present invention, and Figure 2 is a plan view. For the sake of explanation, explanations for the numbered elements having the same structure as in FIG. 4 will be excluded. In FIG.
ilLa and changes the flow downward, then the inner cylinder 20
The flow temporarily flows parallel to the rotating shaft 23, 24 through the inlet 25, and then reaches the metering chamber.
2, and the number of revolutions of the non-circular rotor at this time is counted to measure the flow rate of the fluid to be measured. This inlet 25 is a fluid passage different from the conventional pressure guiding hole 251 shown in FIG. 4, and its cross-sectional area is selected to be equal to or larger than the cross-sectional area of the inlet 11. This is designed to reduce the influence of dynamic pressure acting on the non-circular rotor. The total pressure, including the dynamic pressure of the inflowing fluid, acts on the outside of the inner cylinder end face through the diameter of the communication port 41 that opens into the upper lid 40 from the upper part, and the diameter of the inflow port 25 from the lower part, and acts on the inside of the inner cylinder end face. Since the average pressure of inflow and outflow pressure acts on the bearing part, a pressure difference is generated in the bearing part from the outside of the inner cylinder to the inside, and this creates driftwood for bearing lubrication, reducing shaft friction and improving accuracy. .

By providing a liquid reservoir 26 concentrically with the rotor shafts 23 and 24 on the end face of the first rotor, liquid is always stored in the liquid reservoir, and when the liquid runs out, a state of solid lubrication occurs, which prevents early bearing wear. 1. This allows for smooth rotation. On the other hand, since the fluid to be measured flows into the inner cylinder through the inlet 25 that opens on the lower end plate of the inner cylinder, the liquid seal between the inner and outer cylinders is also completely sealed by flat packings 51, 52, etc. The gap 60 between the inner and outer cylinders is also large, and since the gap 60 is filled with liquid at the outflow pressure, a stable pressure balance is provided, and the influence of piping stress applied to the outer cylinder is almost eliminated. I never receive it.

Suke-ichiichien.

As is clear from the above description, according to the present invention, the effect of dynamic pressure that adversely affects a non-circular rotor can be reduced and
Furthermore, the bearing part is equipped with a fluid lubrication flow to reduce bearing friction and completely eliminate the amount of leak bypassing between the inner and outer cylinders, making it unnecessary to increase the machining accuracy of the inner and outer cylinders and eliminating the effects of piping stress. Therefore, an inexpensive and highly accurate flowmeter can be realized.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views for explaining an embodiment of a positive displacement flowmeter according to the present invention, and FIG. 3 is a configuration diagram for explaining an example of a conventional integral positive displacement flowmeter. Figure 4 shows
FIG. 2 is a diagram for explaining an example of a conventional separate positive displacement flowmeter. DESCRIPTION OF SYMBOLS 10... Outer cylinder, 20... Inner cylinder, 21, 22... Non-circular rotating gear, 23.24... Rotating shaft, 26... Liquid reservoir. 30...Outer cylinder lid, 40...Upper lid. Patent author Oval Equipment Industry Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) a pair of non-circular rotating gears that rotate in proportion to the flow rate and mesh and rotate around an integrally fixed shaft;
The non-circular rotary gears are rotatably housed with a small gap, and an inflow hole communicates with the inflow fluid at the bottom, a pair of shaft holes through which one shaft end of the rotation shafts of the pair of non-circular rotary gears is inserted, and side surfaces. an inner cylinder bored with an outflow hole for introducing outflow fluid into the inner cylinder; a pressure introduction hole that is mounted on the inner cylinder and communicates with the inflow hole; and the other shaft end of the rotating shaft of the pair of non-circular rotating gears is inserted through the inner cylinder. an inner cylindrical part composed of an upper lid having a shaft hole; and a means for connecting the inner cylindrical part to the inflow hole, the outflow hole and the external flow pipe by loosely inserting the inner cylindrical part into both end surfaces through a sealing material in a fluid-tight manner; and an outer cylinder lid that fluid-tightly presses and attaches the inner cylinder part to the outer cylinder, and prevents the pressure difference between the inflow and outflow parts of the fluid to be measured into the sliding part of the rotating shaft. A positive displacement flowmeter characterized by adding: (2) The volumetric flowmeter according to claim (1), characterized in that both end faces of the non-circular rotating gear have liquid reservoirs cut out concentrically with the rotating shaft.