JP3365962B2 - Area type flow meter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an area type flow meter having a damper mechanism. 2. Description of the Related Art In an area type flowmeter, as is well known, a fluid to be measured introduced from below in a tapered pipe or straight pipe is throttled by a float, and a pressure difference is generated before and after the float. The float rises due to the upward force due to this pressure difference, but as it rises, the passage area increases and the pressure difference decreases, so that the float eventually stops at a position where the effective weight of the float and the upward force are balanced . Since the passage area determined by the stationary position and the flow rate are in a proportional relationship, the position is detected to determine the flow rate. In this type of area type flow meter, when a sudden change in the flow rate occurs, the position of the float also changes rapidly following the change. Usually, this type of area type flow meter is provided with an upper stopper and a lower stopper, and when a sudden change in position of the float occurs, the float or the float rod hits these stoppers and is forcibly stopped. The float, the float rod, the stopper, and the like are damaged by the impact due to the forced stop. As means for preventing damage to a float, a float rod, a stopper, and the like due to a rapid change in flow rate,
Conventionally, a damper mechanism has been known. For example, Japanese Utility Model Application Laid-Open No. 63-84517 discloses a structure in which a damper pipe is provided above a pipe having a tapered pipe portion, and a damper is inserted into the damper pipe. The upper end of the damper pipe is welded to the pipe body, and the lower end is opened as an insertion port for the damper. The damper is attached to the float shaft so as to freely move in the radial direction of the float shaft. According to this structure, the contact resistance between the damper pipe and the damper when the float shaft moves up and down can be reduced. Since the damper pipe is attached to the pipe having the tapered pipe by welding, the damper pipe does not move and the damper floats in the radial direction of the float axis. [0005] In the case of this prior art,
Since the damper pipe is welded to a pipe having a tapered pipe, displacement during welding, distortion due to welding,
And, due to processing errors, etc., between the center position of the damper pipe and the center position of the pipe where the float axis should be placed
An assembly error may occur. In the prior art, since the damper is attached to the float shaft so that it can freely move in the radial direction of the float shaft, there is no problem if the assembly error is within the range of movement of the damper. However, in the actual assembling process, the displacement of the damper pipe does not always fall within the range of movement of the damper. In many cases, the damper pipe causes an error beyond the range of movement of the damper. In such a state, the contact resistance between the outer peripheral surface of the damper and the inner wall surface of the damper pipe increases, and the normal operation of the float and the float shaft is impaired, and the flow rate measurement accuracy decreases. It is an object of the present invention to provide an area type flowmeter capable of avoiding a decrease in flow measurement accuracy due to processing and assembly errors. In order to solve the above-mentioned problems, an area type flowmeter according to the present invention includes a tube, a float rod, and a damper mechanism. The pipe has a flow measurement pipe section, an inflow port, and an outflow port, and the flow measurement pipe section includes a flow path from the inflow port to the outflow port. [0010] The float rod includes a rod portion and a float. The float is provided on the rod portion, and is arranged in the flow rate measuring tube portion of the tube. [0011] The damper mechanism includes a cylinder and a piston. The cylinder has an inner cavity, one end of the inner cavity is opened, and the other end is attached to a fixture provided on the tube so as to be swingable in a radial direction of the tube. ing. The piston is provided on the rod portion, has an outer shape capable of sliding in the inner cavity, and is inserted into the inner cavity of the cylinder. In the area type flow meter according to the present invention, the tube has a flow measuring tube, an inlet, and an outlet, and the flow measuring tube includes a flow path from the inlet to the outlet. In. Therefore, a flow path is formed from the inflow port to the outflow port through the flow rate measurement pipe section. [0013] The float rod includes a float, and the float is disposed in the flow measuring pipe section. Therefore, the fluid to be measured introduced into the flow measurement pipe section from the inflow port is throttled by the float, and a pressure difference is generated before and after that. The float rises by receiving the upward force due to the pressure difference. However, as the ascent increases, the passage area increases and the pressure difference decreases, so that the float eventually stops at a position where the effective weight of the float and the upward force are balanced. Since the passage area determined by the stationary position and the flow rate are in a proportional relationship, the position is detected to determine the flow rate. Further, the area type flow meter according to the present invention has a damper mechanism. The damper mechanism includes a cylinder and a piston. The cylinder has an inner cavity, one end of the inner cavity is opened, and the other end is attached to a fixture provided in the tube. The piston is provided in the rod portion, has an outer shape capable of sliding in the inner cavity, and is inserted into the inner cavity of the cylinder. According to the damper mechanism having the above structure, when a sudden change in the flow rate occurs, braking is applied to the float or the float rod by the cylinder constituting the damper mechanism and the piston. For this reason, the float, the float rod, the stopper, and the like are protected from damage caused by a sudden change in the flow rate. Further, the cylinder of the damper mechanism has the other end attached to a fixture provided on the tube so as to be swingable in the radial direction of the tube. According to the above structure of the present invention, when an error occurs between the cylinder of the damper mechanism and the piston attached to the float rod, the cylinder of the damper mechanism is, with respect to the fixture provided in the pipe,
Swings in the radial direction of the tube to absorb the error. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism. A fixing device for supporting the float rod,
For example, even when a processing error or an assembly error occurs in the stopper or the like, the cylinder of the damper mechanism swings in the radial direction of the tube relative to the fixture provided in the tube, and absorbs the error. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism. FIG. 1 is a sectional view showing one embodiment of an area type flow meter according to the present invention. This example shows an area flow meter for measuring gas flow. The area type flowmeter according to the present invention includes a tube 1, a float rod 2, and a damper mechanism 3. The pipe 1 includes a flow rate measuring pipe 11 and an inflow port 1.
2 and an outlet 13. The flow measurement pipe section 11 includes a flow path from the inlet 12 to the outlet 13. In the embodiment, the flow measuring pipe section 11 is formed of a tapered pipe. A straight pipe section 14 is continuous below the flow rate measuring pipe section 11 constituted by a tapered pipe, and another straight pipe section 15 is continuous above the flow rate measuring pipe section 11. The inflow port 12 is provided at a lower end of the straight pipe section 14, and the outflow port 13 is provided at an upper end of the straight pipe section 15.
The lower end of the straight pipe section 14 is provided with a flange 71 for connecting an external pipe, and the upper end of the straight pipe section 15 is provided with a flange 72 for connecting an external pipe. The float rod 2 includes a rod portion 21 and a float 22. The float 22 is provided on the rod portion 21 and is arranged in the flow rate measuring tube portion 11 of the tube 1. The float rod 2 has a permanent magnet 4 enclosed therein.
Having. 5 is a flow rate indicating and converting device, 61 is a flow rate scale, and 62 is a flow rate indicating needle. In the area type flow meter according to the present invention, the pipe body 1 comprises a flow rate measuring pipe section 11, an inflow port 12, and an outflow port 13.
And the flow measuring pipe section 11 is connected from the inlet 12 to the outlet 1
3 is included. Therefore, a flow path from the inflow port 12 to the outflow port 13 through the flow rate measurement pipe section 11 is formed. The float rod 2 includes a float 22. Since the float 22 is disposed in the flow measuring tube 11, the fluid to be measured such as gas introduced into the flow measuring tube 11 from the inflow port 12 is provided. The float 22 is squeezed, and a pressure difference is generated before and after that. The float 22 rises due to the upward force due to this pressure difference, but as it rises, the passage area increases and the pressure difference decreases, so that the float 22 eventually stops at a position where the effective weight of the float 22 and the upward force are balanced. I do. Since the passage area determined by the stationary position and the flow rate are in a proportional relationship, the position is detected to determine the flow rate. In the case of the embodiment, the flow value at the stationary position of the float 22 is indirectly transmitted to the flow indicator needle 62 by the permanent magnet 4 and the magnetic coupling means provided in the conversion device 5, It is read from the position of the pointer 62. Further, the area type flow meter according to the present invention includes a damper mechanism 3. The damper mechanism 3 includes a cylinder 31
And a piston 32. FIG. 2 is an enlarged sectional view showing a part of the damper mechanism 3. The cylinder 31 has an inner cavity 311, and one end of the inner cavity 311 is open. The other end of the cylinder 31 is attached to a fixture 81 fixed to the tubular body 1 so as to be swingable in the radial direction of the tubular body 1. The fixture 81 is connected to the flange 72 by means such as a screw. In mounting the cylinder 31 to the fixture 81, as shown in FIG. 2, a hole 811 is provided in the center of the fixture 81, and the upper end of the cylinder 31 is hooked inside the hole 811. The cylinder 31 has a flange portion 812 at the tip end, and the upper end of the cylinder 31 is hooked on the flange portion 812. The upper end of the cylinder 31 has a small-diameter portion 312 having an outer diameter d1 smaller than the inner diameter D1 of the hole 811 and a large-diameter portion 313 provided thereon. The outer diameter d2 of the large diameter portion 313 is larger than the hole diameter D1 of the hole 811. Therefore, the cylinder 31
Is hooked into the hole 811 of the fixture 81,
The tube body 1 can swing in the radial direction by a clearance caused by a difference between the hole diameter D1 of the hole 811 and the outer diameter d1 of the small diameter portion 313. The clearance due to the difference between the hole diameter D1 of the hole 811 and the outer diameter d1 of the small diameter portion 313 is an example, but is 2 m.
Set to about m. For example, the hole diameter D1 of the hole 811 is 12
mm, the outer diameter d1 of the small diameter portion 313 is selected to be 10 mm. The piston 32 is connected to the inner cavity 3 of the cylinder 31.
With respect to the inner diameter of 11, the outer diameter is selected so that substantially no leakage occurs. In the embodiment, since the inner cavity 311 of the cylinder 31 has a cylindrical shape, the piston 32 has a corresponding cylindrical shape. The piston 32 is provided on the rod portion 21. The piston 32 has an inner cavity 311.
Having an outer shape capable of sliding inside, and an inner cavity 31 of the cylinder 31
1 is inserted. According to the damper mechanism 3 having the above-described structure, when a sudden change in the flow rate occurs, braking is applied to the float 22 or the float rod 2 by the cylinder 31 and the piston 32 constituting the damper mechanism 3. For this reason, the float 22, the float rod 2, the stopper, and the like are protected from damage caused by a sudden change in the flow rate. As described above, the embodiment shows the area type flow meter for measuring the gas flow rate, and the cylinder 3 constituting the damper mechanism 3
The inside of one inner cavity 311 contains air substantially equal to the atmospheric pressure. The above-described braking action is applied to the piston 32 by the spring property of the air. Further, the cylinder 31 of the damper mechanism 3 is
The other end side of the fixing device 81 provided in the tubular body 1
Is mounted so as to be able to swing in the radial direction. In this respect, the damper pipe is clearly different from the prior art in which the damper pipe is integrally fixedly attached to the pipe body 1 having the tapered pipe portion.
According to the above structure of the present invention, assembly such as welding the cylinder 31 of the damper mechanism 3 to the pipe 1 is unnecessary. When an assembly error, a processing error, or the like occurs between the cylinder 31 of the damper mechanism 3 and the piston 32 attached to the float rod 2, the cylinder 31 of the damper mechanism 3 is fixed to the fixture provided on the pipe 1. It swings in the radial direction of the tube body 1 with respect to 81 to absorb the error. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism 3. Also, when a machining error or an assembly error occurs in the fixture 81 supporting the float rod 2 or the like, the cylinder 31 of the damper mechanism 3 moves the fixture 81 provided in the pipe 1 into a pipe. It swings in the radial direction of the body 1 and absorbs the error. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism 3. Further, as means for connecting the piston 32 to the rod portion 21 of the float rod 2, in the embodiment, stoppers 33 and 34 such as so-called C-shaped washers are used.
The float rod 21 is an axial end face 32 of a piston 32.
1 and the stoppers 33, 3 on both sides.
4 is used to hold down. Stopper 3
Sealing packings 35, 36 are arranged inside the packings 3, 34, and the packings 35, 36 are held by the stoppers 33, 34.
Is pressed against the end face of the piston 32. Packing 3
5 and 36, the air inside the inner cavity 311 is
It is provided in order to prevent a leak from a gap of the float rod 2 penetrating through the end face of the brake rod 2 and to reduce the braking action. As shown in FIG. 3, a lower stopper 82 is provided at the lower end of the tube 1. The lower stopper 82 is attached to the inside of the lower flange 71 by, for example, screwing. Float rod 2
A lower guide 83 is fixedly attached to the lower end of the rod portion 21. The outer diameter of the lower guide 83 is determined so that a clearance is secured between the lower guide 82 and the inner surface of the straight pipe portion 14 when the lower end of the rod portion 21 contacts the lower stopper 82. Clearance is an example,
It is set to about 0.3 mm. With such a clearance, it is possible to allow the float rod 2 to swing in the radial direction of the tubular body 1 even on the lower end side, thereby absorbing an assembly error and a processing error. FIG. 4 is a sectional view showing another embodiment of the area type flow meter according to the present invention, and FIG. 5 is an enlarged view showing a damper mechanism in the area type flow meter shown in FIG. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals. In this embodiment, the outlet 13 is provided on the side of the straight pipe portion 15. After flowing through the inlet 12, the fluid passes through the straight pipe section 14 and the flow rate measuring pipe section 11, changes its flow in a right angle direction, and flows out of the outlet 13 to an external pipe (not shown). A flange 73 is provided at the upper end of the straight pipe portion 15, and another flange 74 is fastened and fixed to the flange 73 by a bolt 751 and a nut 752. Between the flange 73 and the flange 74,
A fixture 81 provided at the lower end of the non-magnetic cylinder 76 is sandwiched via a gasket or the like. Non-magnetic cylinder 7
Inside the rod 6, a rod-shaped permanent magnet 4 embedded integrally on the axis of the float rod 2 is arranged. Non-magnetic cylinder 76
Is provided with a ring-shaped permanent magnet 78 that is magnetically coupled to the permanent magnet 4 and moves up and down following the up and down movement of the permanent magnet 4. From the position of the ring-shaped permanent magnet 78, the position of the float 22, that is, the flow value is read. A damper mechanism 3 is provided at an intermediate portion in the longitudinal direction of the float rod 21. Damper mechanism 3
The cylinder 31 is disposed inside the straight pipe portion 15, and one end in the axial direction can swing on the flange portion 812 of the fixed portion 81 provided to protrude from the lower end of the non-magnetic cylinder 76. It is hung on. According to the damper mechanism 3 having the above-described structure, when a sudden change in the flow rate occurs, braking is applied to the float 22 or the float rod 2 by the cylinder 31 and the piston 32 constituting the damper mechanism 3. For this reason, the float 22, the rod portion 21, the stopper, and the like are protected from damage caused by a sudden change in the flow rate. Further, the cylinder 31 of the damper mechanism 3
The other end side of the fixing device 81 provided in the tubular body 1
Is mounted so as to be able to swing in the radial direction. According to this structure, assembling errors, processing errors, and the like are absorbed by the cylinder 31 swinging in the radial direction of the tube 1. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism 3. Further, even when a machining error or an assembly error occurs in the fixture 81 supporting the float rod 2 or the like, the cylinder 31 of the damper mechanism 3 moves the fixture 81 provided in the pipe 1 into a pipe. It swings in the radial direction of the body 1 and absorbs the error. For this reason, it is possible to avoid a decrease in flow rate measurement accuracy due to the assembled state of the damper mechanism 3. FIG. 6 is a sectional view showing another embodiment of the area type flow meter according to the present invention. In the drawings, the same components as those shown in FIGS. 4 and 5 are denoted by the same reference numerals. In this embodiment, the conversion device 5 is provided in the portion of the non-magnetic cylinder 76. The conversion device 5 includes a case 50
Is provided with a permanent magnet 51 that is magnetically coupled to and follows the permanent magnet 4 provided on the float rod 2. The movement of the permanent magnet 51 is detected by a converter 52 provided inside the case 50. The case 50 is provided with a protection cylinder 53 for protecting the non-magnetic cylinder 76.
The other components are almost the same as those of the embodiment shown in FIGS. As described above, according to the present invention, it is possible to provide an area type flow meter capable of avoiding a decrease in flow rate measurement accuracy due to machining and assembly errors.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one embodiment of an area flow meter according to the present invention. FIG. 2 is an enlarged sectional view showing a part of a damper mechanism of the area type flow meter shown in FIG. FIG. 3 is an enlarged sectional view showing a lower stopper portion of the area type flow meter shown in FIG. 1; FIG. 4 is a sectional view showing another embodiment of the area type flow meter according to the present invention. FIG. 5 is an enlarged view showing a part of a damper mechanism in the area type flow meter shown in FIG. 4; FIG. 6 is a sectional view showing another embodiment of the area type flow meter according to the present invention. [Description of Signs] 1 Pipe 2 Float rod 21 Rod portion 22 Float 3 Damper mechanism 31 Cylinder 32 Piston 13 Inlet 14 Outlet 15 Partition wall

Claims (1)

(57) [Claim 1] An area type flow meter including a pipe, a float rod, and a damper mechanism, wherein the pipe has a flow measurement pipe section, an inflow port, An outlet, the flow measurement pipe section includes a flow path from the inlet to the outlet, the float rod includes a rod section, and a float, and the float includes the float, The damper mechanism includes a cylinder and a piston, and the cylinder has an inner cavity, and one end of the inner cavity is provided with The opening is provided, and the other end side is attached to a fixture provided in the tube so as to be swingable in a radial direction of the tube, and the piston is provided in the rod portion, and the piston is provided in the inner cavity portion. Having an outer shape capable of sliding the inside of the inner cavity of the cylinder. Area flowmeter is inserted.