JPH1164065A - Flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of an inlet pipe and an outlet pipe, while avoiding the deterioration of the molding accuracy. SOLUTION: In a flowmeter in which a pair of rotating bodies 7 and 7 are rotatably housed in an actuating chamber 2, formed into a gear housing 1 and an inlet pipe 5 and an outlet pipe 6 are respectively connected to an inlet passage 3 and an output passage 4 communicated with the chamber 2, and then detectors which detect the angles of rotation of the rotating bodies 7 are arranged on the outside of the chamber 2 and which measures the flow rate of a fluid from the angles of rotation of the rotating bodies 7 detected by means of the detectors, the housing 1 is formed by molding a material having high moldability, and the pipes 5 and 6 are formed of a material which is softer than that of the housing 1. Even if excessive tightening forces were to be applied to the inlet and outlet pipes 5 and 6 when the pipes 5 and 6 are connected to a metallic pipe, the breakage of the pipes 5 and 6 can be prevented, because the pipes 5 and 6 bend and absorb the forces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter, and more particularly to an improvement in a joint structure of an inlet pipe and an outlet pipe for flowing a fluid through a working chamber.

[0002]

2. Description of the Related Art As a conventional flow meter, for example, a non-circular gear type flow meter is known. In the non-circular gear type flow meter, a pair of non-circular gears rotating according to the flow rate of fluid are rotatably housed in a working chamber of a gear housing, and an inlet passage and an outlet passage respectively communicating with the working chamber are provided in The inlet pipe and the outlet pipe are connected respectively, and a detector for detecting the rotation angle of one non-circular gear is arranged outside the working chamber, and is configured to measure the flow rate from the rotation angle by detection of the detector. I have.

[0003] In this type of conventional flowmeter, the gear housing, the inlet pipe and the outlet pipe are integrally formed. In this case, a composite resin mixed with glass, carbon, or the like is used to increase the molding accuracy.

[0004]

However, since a flow meter integrally formed of a composite material resin tends to be hard and brittle, for example, when this flow meter is mounted on a liquid chemical supply device, If an excessive pipe tightening force is applied to the inlet pipe and the outlet pipe at the time of fastening to the metal pipe pipe, the joint may be damaged.

An object of the present invention is to provide a flow meter capable of preventing breakage of an inlet pipe and an outlet pipe while avoiding a decrease in molding accuracy.

[0006]

A flow meter according to the present invention comprises:
A rotating body that rotates according to the flow rate of the fluid is rotatably housed in a working chamber formed in the housing, and an inlet pipe and an outlet pipe are connected to an inlet passage and an outlet passage that respectively communicate with the working chamber. A detector for detecting the rotational movement of the rotating body is disposed outside the working chamber. In the flow meter for measuring the flow rate from the rotation angle by the detection of the detector, the housing has strong chemical resistance. The inlet pipe and the outlet pipe are formed of a chemical-resistant synthetic resin softer than the housing.

According to the above-described means, since the inlet pipe and the outlet pipe are formed of a soft resin, when the pipe is fastened to a rigid pipe made of metal or the like, excessive tightening of the pipe should occur. Even if a force is applied, an excessive tightening force can be absorbed by bending the inlet pipe and the outlet pipe, and breakage thereof can be prevented.

[0008]

FIG. 1 is a partially cutaway side view showing a non-circular gear type flow meter according to an embodiment of the present invention. FIG.
Is a plan sectional view thereof. FIG. 3A is a front view thereof,
(B) is a front sectional view. FIG. 4 is a side sectional view showing a method of forming a non-circular gear type flow meter according to an embodiment of the present invention.

In this embodiment, the flow meter according to the present invention is configured as a non-circular gear type flow meter. The non-circular gear type flow meter includes a gear housing 1 formed in a substantially rectangular parallelepiped using PPS (polyphenylene sulfide), which is an example of an engineering resin having good moldability and chemical resistance. The working chamber 2 is opened at one end surface (hereinafter, referred to as an upper surface) of the gear housing 1. The working chamber 2 is formed in a column-shaped space formed by arranging two sets of semicircles and squares in a cross shape. In addition, an inlet passage 3 and an outlet passage 4 are arranged in the gear housing 1 in a 180-degree direction (hereinafter, referred to as a front-rear direction).
The gear housing 1 is opened to communicate with each other, and the front and rear surfaces of the gear housing 1 are made of a fluorine-based resin, which is an example of a resin that is softer and more resistant to chemicals than the gear housing 1, and will be described later. The inlet pipe 5 and the outlet pipe 6 formed as described above are provided so as to be fluidly connected to the inlet passage 3 and the outlet passage 4, respectively.

A non-circular gear 7 as a rotating body is provided in the working chamber 2.
The two non-circular gears 7, 7 are rotatably supported by respective support shafts 8 erected in parallel with each other on the gear housing 1. The non-circular gear 7 is formed using carbon or resin (for example, PPS). On the upper surface of one non-circular gear 7, a reflecting plate 9
Is mounted on the upper surface by being fitted into a circular hole which is disposed concentrically with the center of rotation. Reflector 9a is provided on the outer periphery of reflector 9
And a plurality of non-reflection portions 9b are arranged alternately at equal intervals in the circumferential direction.

On the upper surface of the gear housing 1, a circular annular groove 10 is disposed so as to surround the opening of the working chamber 2, and is submerged. A circular O-ring 11 is housed in the annular groove 10. . A case 12 is superposed on the gear housing 1 with an O-ring 11 interposed therebetween. The case 12 is formed of the same chemical-resistant synthetic resin as the gear housing 1 and is formed in substantially the same planar shape as the gear housing 1. I have. The gear housing 1 and the case 12 are fastened by bolts 13 arranged at four corners thereof.

A recess 14 is arranged on the lower surface of the bottom wall of the case 12 at a position facing the peripheral portion of the reflection plate 9 of one of the non-circular gears 7 and is sunk downward. A transparent member 15 formed in a small circular plate shape is fitted and fixed with an adhesive or the like. A pair of through-holes 17 and 18 are disposed in the bottom wall of the case 12 at positions facing the transparent member 15, and are opened in such a manner that their extended lines are inclined so as to substantially intersect with the surface of the reflection plate 9. I have. One through hole 1
A light-emitting element 19 is arranged above the upper part 7 and inserted so as to project light at a minimum portion around the reflection plate 9, and a light-receiving element 20 is inserted above the other through-hole 18 from the reflection part 9 a. It is arranged and inserted so as to receive the reflected light. And
The light emitting element 19 and the light receiving element 20 are connected to an input / output device 21 installed in the installation room 16 of the case 12, and the installation room 16 incorporates electronic components or electronic devices (not shown) required for measurement. Have been.

In this embodiment, the inlet pipe 5
A threaded joint 22 to which a female screw coupling 24 (see the imaginary line in FIG. 1) is attached is formed integrally with the outer peripheral portion of the outlet pipe 6. An engagement portion 23 for engaging a tool such as a wrench is formed at the base end of the threaded joint 22.

The inlet pipe 5 and the outlet pipe 6 are insert-molded in the gear housing 1 as shown in FIG. 4 includes an upper die 31, a lower die 32, and an inlet pipe holding unit 3.
3 and an outlet pipe holding portion 34,
These form a cavity 35. That is, the gear housing forming portion 36 is formed in cooperation with the mating surface of the upper die 31 and the lower die 32, and the upper die 3
An operating chamber forming portion 37 is provided so as to protrude from the mating surface 1.
Further, an annular groove forming portion 38 is protruded from the mating surface of the upper die 31.

An inlet pipe holding portion 33 is formed on one side of the gear housing forming portion 36 on the mating surface of the upper die 31 and the lower die 32, and an outlet pipe holding portion 34 is formed on the other side. I have. The inlet pipe holding portion 33 holds the inlet pipe 5 with its inner end inserted into the gear housing forming portion 36. The outlet pipe holding section 34 holds the outlet pipe 6 with its inner end inserted into the gear housing forming section 36.

At the time of injection molding of the gear housing 1, the inlet pipe 5 and the outlet pipe 6, which are formed of a fluorine resin in advance, are connected to the inlet pipe holder 33.
In a state where the resin is set in the outlet pipe holding portion 34, a resin as a molding material is filled into the cavity 35 from the gate 39 opened at an appropriate portion of the mating surface of the upper die 31 and the lower die 32 and is cured. Then, the inlet pipe 5 and the outlet pipe 6 are insert-molded together with the gear housing 1 and the working chamber 2. At this time, the inlet pipe 5 and the outlet pipe 6
A core 40 for preventing leakage is inserted in advance in each hollow portion.

Next, the operation will be described. When a liquid to be measured as a working fluid is introduced from the inlet pipe 5 into the working chamber 2 through the inlet passage 3, the liquid works in the working chamber 2, and then is drawn out of the outlet pipe 6 through the outlet passage 4. Go. When the liquid passes through the working chamber 2, a pair of non-circular gears 7 meshing with each other and partitioning the working chamber 2,
7 is rotated by the flow in the direction shown by the dashed arrow in FIG. On the other hand, the light from the light emitting element 19 passes through the transparent member 15 and irradiates the reflecting plate 9 of the non-circular gear 7 to be reflected. The reflected light passes through the transparent member 15 and is received by the light receiving element 20. At this time, since there is a large difference in reflectance between the reflecting portion 9a and the non-reflecting portion 9b, the rotation angle of the non-circular gear 7 can be measured based on the output of the light receiving element 20. Since the rotation angle of the non-circular gear 7 is proportional to the flow rate of the liquid rotating the non-circular gear 7, the flow rate is substantially measured by measuring the rotation angle.

For example, when a non-circular gear type flow meter is mounted on a liquid chemical supply device, as shown by imaginary lines in FIG. 1, rigid metal pipes are formed in the inlet pipe 5 and the outlet pipe 6. The female threaded coupling 24 is connected to the threaded joint 2 in a state where the pipe 25 made of stainless steel is abutted against the inlet pipe 5 and the outlet pipe 6, respectively.
It is screwed into 2 and fixed. At this time, a tool (not shown) such as a wrench is engaged with the engaging portion 23 and is prevented from rotating.

According to the present embodiment, the inlet pipe 5
Since the outlet pipe 6 is insert-molded in the gear housing 1 by a fluorine resin, which is an example of a flexible resin, when the metal pipe 25 is fastened to the inlet pipe 5 and the outlet pipe 6, Even if an excessive pipe tightening force is applied, the excessive pipe tightening force can be absorbed by bending the inlet pipe 5 and the outlet pipe 6, and damage to the inlet pipe 5 and the outlet pipe 6 can be prevented. Prevent beforehand.

On the other hand, since the gear housing 1 is formed of PPS, which is an example of an engineering resin having good moldability, it is possible to prevent a reduction in molding accuracy and to reduce the performance of the non-circular gear flow meter. Can be avoided.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.

The inlet pipe and the outlet pipe are not limited to being formed by using a fluorine resin, but may be formed of another flexible resin. Further, the inlet pipe and the outlet pipe are not limited to being insert-molded in the gear housing, but may be integrally formed by a so-called two-color molding method or the like.

[0023]

As described above, according to the present invention,
Because the inlet pipe and outlet pipe are formed of a softer resin than the gear housing,
When fastened to a metal rigid pipe,
Even if an excessive pipe tightening force is applied, the inlet pipe and the outlet pipe bend, so that the excessive tightening force can be absorbed and the breakage thereof can be prevented. On the other hand, since the gear housing is formed of a material having good moldability, a decrease in molding accuracy can be avoided, and a decrease in detection accuracy of the flowmeter can be prevented.

[Brief description of the drawings]

FIG. 1 is a partially cut-away side view showing a non-circular gear type flow meter according to an embodiment of the present invention.

FIG. 2 is a plan sectional view thereof.

3A is a front view thereof, and FIG. 3B is a front sectional view thereof.

FIG. 4 is a side sectional view showing a method of forming a non-circular gear type flow meter according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gear housing, 2 ... Working chamber, 3 ... Inlet passage, 4 ...
Exit passage, 5 ... Inlet pipe, 6 ... Outlet pipe, 7 ... Non-circular gear, 8 ... Support shaft, 9 ... Reflector, 9a ...
Reflecting portion, 9b Non-reflecting portion, 10 annular groove, 11 O-ring, 12 case, 13 bolt, 14 recess, 15
Transparent member, 16 installation room, 17, 18 through hole, 19 light emitting element, 20 light receiving element, 21 input / output device, 22 screw coupling, 23 engagement part, 24 female screw coupling, 2
5 metal pipe, 30 molding die, 31 upper die, 32
... lower mold, 33 ... inlet pipe holding part, 34 ... outlet pipe holding part, 35 ... cavity, 36 ... gear housing forming part, 37 ... working chamber forming part, 38 ... annular groove forming part, 39 ... gate, 40 ... Nakako.

Claims (1)

[Claims] A rotating body that rotates in accordance with a flow rate of a fluid is rotatably housed in a working chamber formed in a housing, and an inlet pipe and an outlet passage are respectively provided in an inlet passage and an outlet passage communicating with the working chamber. Pipes are connected to each other, and a detector for detecting the rotational movement of the rotating body is disposed outside the working chamber.In a flowmeter that measures a flow rate from the rotational movement by detection of the detector, the housing includes: A flow meter, wherein the inlet pipe and the outlet pipe are formed of a chemical-resistant synthetic resin that is softer than the housing and is formed of a strong chemical-resistant synthetic resin.