JP3289097B2 - Piston reciprocating flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston reciprocating flow meter.

[0002]

2. Description of the Related Art As a flow meter of this type, for example, there is a four-piston type flow meter provided with two pairs of pistons which work in pairs. This is provided with a casing 2 provided with two pairs of cylinders 1A, 1B; 1C, 1D which are arranged to face each other on two axes orthogonal to each other as shown in FIGS. The casing 2 includes the cylinder 1
A, 1B; 1C, 1D; a casing body 4 defining a center as a communication chamber 3 where cylinders are gathered; and an upper lid 5 and a lower cover for covering upper and lower openings of the casing body 4 communicating with the communication chamber 3. The cover 6 includes a lid 6 and side lids 7, 7,... Covering the outer openings of the cylinders.

[0003] Pistons 8A, 8B; 8C, 8D are slidably fitted to the cylinders 1A, 1B; 1C, 1D, respectively. The pair of pistons 8A and 8B and 8C and 8D are connected by yokes 9A and 9B, respectively.
The yokes 9A and 9B are composed of a pair of curved left and right arm portions 10 and a connecting portion 11 for connecting the pair of arm portions 10. Both ends of the pair of arm portions 10 correspond to the corresponding pistons 8A, 8B or 8C. Under the state of being in contact with the back surface of 8D, each piston is fixed to the piston by a bolt 12 inserted from the front surface side of the piston. Each of the pistons includes a piston body 13, a seal member 14 and a retainer 15 arranged on the outer surface side of the piston body 13, and the retainer 15
Thus, the piston body 13 is integrated.

In the casing 2, a rotating shaft 16, which extends the communication chamber 3 in the vertical direction, is rotatable via a bearing 17 provided on the upper lid 5 and a bearing 18 provided on a lower portion of the casing body 4. Two points are supported. An eccentric cam 19 is attached to the rotating shaft 16 in the communication chamber 3, and each piston 8 A, 8 B; 8 C, 8 D
A cam roller 22 that is rotatably attached to a boss portion 20 protruding from the rear surface of the base member with a bolt 21 is in contact with the boss portion 20. Each of the yokes 9A and 9B is extended at the upper and lower positions of the eccentric cam 19, and the central portion thereof is curved upward or downward to avoid interference with the eccentric cam 19.
The pair of arm portions 10 of the yokes 9A and 9B have their central portions set at the minimum interval allowing the rotation shaft 16 to pass therethrough, while both ends thereof are formed at the cam rollers 2A and 9B.
2 is set to be wide so as to avoid interference with the two.

Also, each piston 8A, 8B; 8C, 8D
Measuring chambers 23A, 23B; 23C, 2
It is partitioned as 3D. Each measuring chamber 23A, 23B
Are formed in a flow path 24A formed in a bottom portion in the casing body 4,
24B (cylinders 1C and 1D are omitted), it is communicated with the inflow port 25 of the cup-shaped lower lid 6 attached to the lower surface of the casing body 4, and further in the lower lid 6, the lower bearing portion 18
Is communicated with the outflow port 26 of the upper lid 5 through the flow path 30 around the communication port 3 and the communication chamber 3. Here, the lower bearing 1
As shown in FIG. 7, 8 is provided in the bridge portion 4b crossing the virtual circular hole 4a, and the flow path 30 is provided by two arc-shaped holes 30a as the remaining portion of the virtual circular hole 4a. ing.

On the other hand, a cup-shaped switching valve 27 is attached to a lower end portion of the rotating shaft 16 which extends through the lower wall of the casing body 4 into the lower cover 6. This switching valve 27
An annular spring receiver 28 which is prevented from rotating with respect to the switching valve 27 is disposed on the bottom side of the switching valve 27. Switching between the spring receiver 28 and the inner bottom surface of the lower lid 6 is performed via the spring receiver 28. Valve 2
A spring (compression spring) 29 that resiliently biases the casing 7 against the casing body 4 is interposed. The switching valve 27 is configured such that one of the measuring chambers 9B is connected to the inflow port 2 by selectively allowing the hollow portion 27a to face one of the flow paths 24A and 24B.
5, the other measuring chamber 9A acts so as to communicate with the outlet 26.

[0007] The four-piston type flow meter constructed as described above has a liquid feeding means (not shown) such as a pump at its inflow port 25.
However, a liquid supply means (not shown) such as an oil supply nozzle is connected to the outlet 26, so that the liquid supply means is put to practical use. And
In the state shown in FIG. 6, the fluid pressure-fed from the liquid feeding means enters the lower lid 6 from the inflow port 25 as shown by the solid line arrow, and further enters one measuring chamber 23B via the flow path 24B. At this time, the other measuring chamber 23A communicates with the outflow port 26, so that a pressure difference causes the pair of pistons 8A, 8A to move.
B moves integrally to the left in FIG. 5, and the fluid in the measuring chamber 23A flows from the outlet 26 through the flow path 24A, the cavity 27a of the switching valve 27, the flow path 30, and the communication chamber 3 as shown by the dotted arrow. It is discharged outside. The leftward movement of the pistons 8A and 8B drives the rotary shaft 16 to rotate 90 degrees via the eccentric cam 19, and at the same time, the switching valve 27 rotates 90 degrees. Then, the pair of pistons 8C and 8D in the other opposed cylinders 2C and 2D move in one direction, the fluid in the corresponding measuring chamber is supplied and discharged, and the rotating shaft 16 is driven to rotate by 90 degrees.

Then, this time, the flow path 24A communicates with the inflow port 25, and the flow path 24B communicates with the outflow port 26. The pair of pistons 8A and 8B move rightward in FIG. While the fluid flows into the measuring chamber 23,
The fluid in B is discharged to the outside. Since the stroke of each pair of pistons is constant,
The amount of fluid discharged per rotation is constant, and therefore, if the number of rotations is measured, the flow rate can be measured.
A similar piston-type flow meter is disclosed in Japanese Utility Model Publication No. 58-7296.
No. 6,086,045.

[0009]

However, in recent gas stations, effective use of space has become an important issue, and the demand for smaller and lighter equipment has been increasing. In order to meet this demand, the flowmeter has also been reduced in size and weight. However, it is most effective to reduce the length of the yokes 9A and 9B, that is, the distance between the pistons. Become. However, in the case of the conventional piston reciprocating flow meter described above, without reducing the measuring ability, that is, when the piston reciprocating distance is made the same as the conventional one and the piston-to-piston distance is reduced,
A flow path 30 is provided around the lower bearing 18 supporting the rotating shaft 16.
Is formed, the flow path 30 becomes narrow,
Accordingly, a new problem that the pressure loss increases has arisen.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a piston reciprocating flow meter capable of reducing the size and weight without increasing the pressure loss.

[0011]

According to the present invention, in order to achieve the above object, a communication chamber communicating with an outflow port is formed in a casing, and a cylinder is provided opposite to the communication chamber with the communication chamber interposed therebetween.
The opposed cylinders are provided with pistons connected by a yoke and interlocked with each other in a pair, and the communication chamber is provided with a rotary shaft extending therethrough in a direction orthogonal to the axis of the cylinder, and a rotation in the communication chamber. An eccentric cam for converting the reciprocating motion of the piston to the rotating motion of the rotary shaft is attached to the shaft, and one side of the rotary shaft extending through the communication chamber has a cylinder defined by the piston. For each of the measuring chambers, a flow path communicating with the measuring chamber is formed between a flow path that houses the rotating shaft therein and communicates with the communication chamber and a flow path that communicates with an inlet formed in the casing. A switching valve for selectively switching communication is provided, and in a piston reciprocating flow meter that measures a flow rate of a fluid by rotating the switching valve integrally with the rotary shaft, the bearing for supporting the rotary shaft is connected to the communication portion. Characterized by being configured to be disposed within.

[0012]

In the piston reciprocating flow meter constructed as described above, the bearing for supporting the rotating shaft is provided in the communicating material, not in the flow passage communicating with the communication chamber in which the rotating shaft is housed. Therefore, even if the casing of the flow meter is reduced in size and weight, a large area of the flow path communicating with the communication chamber in which the rotating shaft is housed can be secured.

[0013]

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

FIG. 1 shows a piston reciprocating flow meter according to the present invention. This embodiment is configured as a four-piston type flow meter, and its overall structure is as follows.
Since they are the same as those shown in FIGS. 5 and 6 above, the same portions are denoted by the same reference numerals and description thereof will be omitted. In the present embodiment, the lower bearing portion 31 that supports the rotating shaft 16 is disposed in the communication chamber 3. As shown in FIG. 2, the bearing portion 31 is provided on a mountain-shaped bridge portion 33 formed integrally with the casing main body 4 so as to cross the circular hole 32 at the lower portion of the casing main body 4. The rotary shaft 16 is disposed at the center of the circular hole 32, and an annular hole 34 around the rotary hole 16 provides a flow path 35 that connects the communication chamber 3 and the inside of the cup of the lower lid 6.

The operation of the flow meter constructed as described above is the same as that of the conventional flow meter (FIGS. 5 and 6), and the reciprocating motion of each pair of pistons 8A and 8B and 8C and 8D accompanying the supply of the fluid. The rotational motion of the rotary shaft 16 is converted via the cam roller 22 and the eccentric cam 19, and the switching valve 2
7 operates so as to switch the flow path, and each measuring chamber 23A, 2
3B; the fluid in 23C and 23D flows into the communication chamber 3 from the annular flow path 35, and is further discharged from the outlet 26 to the outside. Since the lower bearing 31 for supporting the rotary shaft 16 is separated from the flow path 35 and disposed in the communication chamber 3, the reciprocating distance of the pistons 8A and 8B; Even if the lengths of the yokes 9A and 9B, that is, the distance between the pistons, are shortened, the flow passage area of the flow passage 35 is sufficiently large, so that the pressure loss does not increase. In addition, since the distance between the upper and lower bearings 17 and 31 that support the rotating shaft 16 at two points is reduced, deformation such as bending of the rotating shaft 16 is less likely to occur, and the rotating shaft 16 may be blurred. The weighing accuracy will be stable as it disappears.

Although the above-described embodiment is configured as a four-piston type, the present invention may instead be configured as a two-piston type in which a pair of pistons are opposed to each other.

FIG. 3 shows a flow meter of this type.
As shown in FIG. 1, there is a type in which a liner 40 is press-fitted into each of the cylinders 1A, 1B; 1C, 1D, and the inner surface of the liner 40 is used as a sliding surface for the pistons 8A, 8B; When such a flow meter is manufactured, the liner 40 is usually press-fitted into the cylinders 1A and 1B;
The inner surface of the liner 40 is ground and finished to a predetermined size and shape. In order to reduce the length of the yokes 9A and 9B, that is, the distance between the pistons, to reduce the size and weight of such a flow meter, each liner 40 comes closer to the communication chamber 3 side. Cylinder 1A, 1
B: On the upper side of 1C and 1D, the liner 40 partially protrudes from the cylinder, and therefore, during grinding after press-fitting, there is a problem that the protruding portion (free portion) is deformed by the processing pressure. Was.

Therefore, in another embodiment of the present invention, as shown in FIGS. 3 and 4, in addition to the configuration of the above embodiment, a guide portion 41 for covering the protruding portion of the liner 40 is formed integrally with the casing body 4. And each cylinder 1A, 1B;
The lengths of C and 1D are substantially extended. With such a configuration, the entire liner 40 is covered with the cylinders 1A and 1B; 1C and 1D and the guide portion 41. Therefore, the liner 40 is used for grinding after press-fitting.
Will not be deformed. In addition, pressure loss can be prevented at the same time.

[0019]

As described above in detail, according to the piston reciprocating flow meter according to the present invention, a sufficient flow passage area can be obtained even if the casing of the flow meter is reduced in size and weight. As a result, the pressure loss does not increase.
In addition, since the support point of the rotating shaft approaches, the blurring of the rotating shaft is prevented, and stability in accuracy can be secured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the structure of a piston reciprocating flow meter according to the present invention.

FIG. 2 is an enlarged plan view showing a part of the flow meter shown in FIG.

FIG. 3 is a longitudinal sectional view showing another embodiment of the present invention.

4 is a plan view showing the flow meter shown in FIG. 3 with a part thereof opened.

FIG. 5 is a cross-sectional view of a conventional piston reciprocating flow meter.

FIG. 6 is a longitudinal sectional view of a conventional piston reciprocating flow meter.

FIG. 7 is an enlarged plan view showing a part of a conventional flow meter.

[Explanation of symbols]

 Reference Signs List 1A to D cylinder 2 Casing 3 Communication chamber 4 Casing main body 8A to D Piston 9A to D yoke 16 Rotating shaft 17 Bearing part 19 Eccentric cam 24A, B Flow path 27 Switching valve 31 Bearing part 33 Bridge part 35 Flow path

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 1/00-9/02

Claims (1)

(57) [Claims] A communication chamber communicating with an outlet is formed in a casing, and a cylinder is provided opposite to the communication chamber with the communication chamber interposed therebetween. The communication chamber is provided with a rotary shaft penetrating and extending in a direction orthogonal to the axis of the cylinder, and the rotary shaft in the communication chamber converts the reciprocating motion of the piston into the rotary motion of the rotary shaft. An eccentric cam is mounted on one side of the rotary shaft extending through the communication chamber, and for each measurement chamber in the cylinder defined by the piston, a flow path communicating with the measurement chamber is provided. A switching valve that selectively switches communication between a flow path that houses a shaft therein and communicates with the communication chamber and a flow path that communicates with an inflow port formed in the casing; And rotate it together A reciprocating piston type flow meter for measuring a flow rate of a fluid, wherein a bearing portion for supporting the rotary shaft is disposed in the communication chamber.