JPH0238817A - Flowmeter using bellows - Google Patents

Abstract

PURPOSE:To measure a fine flow rate by allowing a bellows inner chamber and a bellows outer chamber to respectively communicate with a pair of the pressure guide small holes opened to the curved inside and outside walls of the bent pipe connected on the way of a flow passage. CONSTITUTION:Electrodeposition bellows 5 is a bellows like member having an extremely thin wall thickness molded by a plating method of a kind and senses fine load with high sensitivity to convert the same to extension/ contraction quantity. A differential transformer 9 has function for converting said extension/contraction quantity to quantity of electricity. That is, AC is applied to a primary coil 10a from a power supply part and the induced voltages different corresponding to the position of a core 11 moving along with the extension and contraction of the electrodeposition bellows 5 are generated in the secondary coils 10b, 10c on both sides of said coil 10a and the difference voltage thereof is converted to a smooth DC by a rectifying circuit. Since the electrodeposition bellows 5 senses the slight difference pressure between the curved outside and inside parts 21a, 21b of a bent pipe 15 to extend and contract, a fine flow rate can be measured from the output signal of the aforementioned differential transformer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flowmeter that measures waves I and Y using a bellows that expands and contracts depending on the pressure in the Ilt path.

[Conventional technology]

Conventionally, as a type of tItt meter, for example, as shown in Figure +52, an orifice (102) is installed in the middle of the flow path (+01).
, and the 2 IT side (1
01a) Bypass flow path (1
In the middle of 03), a total of 4 parts (+04) consisting of a transparent Taber tube (+05) and a floater (+07) loosely inserted into its inner peripheral space (108) are connected.

In other words, this flowmeter has a lot
) is generated (the upstream side (Iota) is higher pressure than the downstream side (lo+b)), and the bypass I11. 7- Ha? )
It is impossible to measure the total flow rate of the flow path (+01) by visually measuring the position of the flow path (+01).

[Problem to be solved by the invention]

However, in the tii meter as described in (b), when the flow rate in the fIL path (+01) decreases and the differential pressure on both sides of the orifice (+05) falls below a certain value,
Because the floaters (+07) completely settled, it was difficult to measure them in low-flow conditions.

In view of such problems, the present invention aims to provide a tii, F& meter that is capable of measuring small flow rates.

[Means to solve the problem]

That is, the flowmeter using a bellows according to the present invention has a cylinder airtightly partitioned into two chambers by an internal bellows, and a detection means for detecting the amount of expansion and contraction of the bellows, and the bellows internal chamber in the cylinder. and the bellows external chamber is characterized in that it communicates with a pair of small pressure guiding holes opened in the curved inner wall and curved outer wall of the curved pipe connected in the middle of the flow path, As the bellows, it is preferable to use an electrodeposited bellows.

[For production]

Considering the flow of fluid in a curved pipe, the flow of fluid that always tries to move in a straight line due to inertia is forced to bend by the inner wall of the curved pipe, so the fluid moves toward the outside of the curve in the curved pipe. Therefore, a pressure difference is generated in the curved pipe such that high pressure is on the outside of the curve and low pressure is on the inside of the curve. And the magnitude of this differential pressure is
It changes depending on the magnitude of the inertia, that is, the magnitude of the flow rate.

The present invention focuses on this point and attempts to measure the flow rate by measuring the differential pressure using a highly sensitive bellows such as an electrodeposited bellows that expands and contracts by sensing even the slightest pressure. The pressure on the inside of the curve and on the outside of the curve in the bent pipe is led to the internal and external chambers of the bellows in the cylinder through a pair of pressure guiding small holes, respectively, and therefore the pressure is proportional to the pressure difference between the two chambers. If the extension mi of the bellows is sensed by an appropriate detection means, the flow rate of the fluid can be determined from the detection result.

〔Example〕

Next, one embodiment of the flowmeter according to the present invention will be described based on Fig. 7t41.

In the figure, (1) is a cylinder, and (5) is the cylinder (
1) One end (2) is fixed to the inner wall and runs inside the cylinder (1).
Electroplated bellows airtightly partitioned into chambers (8) and (7), (8
) is a spring member that is located in the bellows external chamber (7) in the cylinder (1) and constantly presses the M1 fitted bellows (5) in the contraction direction. (9) is a differential transformer as a means for detecting the amount of expansion and contraction of the electrodeposited bellows (5);
) A primary coil (10a) and a secondary coil (10b) provided on the outer periphery of the small diameter portion (4) formed on the other end (3) side.
(10c) and the small diameter fjl! (4) It consists of a core (II) provided on the inner periphery so as to be freely movable in the axial direction and connected to the free end of the electrodeposited bellows (5) via a rod (12).

On the other hand, (15) is a bent pipe connected to the middle of the flow path (not shown), which is curved 90' to form a circular arc, and the curved outer wall at the longitudinal center of the chain part pipe (15). (+8a) (the outermost wall surface with respect to the center of the arc formed by the curved pipe (+5)) and the curved inner wall (+8b) (
A pressure guiding small hole (17) (+8) is opened in the innermost surface of the bent pipe (15) with respect to the center of the interior.
'f - radially opposed. and the curved outer wall (I
The pressure impulse small hole (17) of I3a) is connected to the manual hole (13) opened at one end (2) of the cylinder (1) via the pressure impulse path (IS), which is shown simplified by the dotted chain line in the figure. It is connected to the bellows internal chamber (8) in the cylinder (1) and communicates with the small pressure guiding hole (+8b) in the curved inner wall (+8b).
18) is connected to the input hole (eye) opened at the other end (3) of the cylinder (1) via another pressure path (20), and is connected to the bellows external chamber (7) in the cylinder (1). ) is in communication.

In the above configuration, the flow path (21) in one bent pipe (15)
When the fluid flows in the direction of the large arrow (X), the fluid will be pushed to the outside of the curve due to its own inertia, resulting in one curve? (15) Flow path (2
In 1), a phenomenon occurs in which the outside portion of the curve (21a) is compressed and becomes high pressure, and conversely, the inside portion of the curve (21b) is compressed by v1 and becomes low pressure. Both relevant subcommittees (
The pressure of 21a) (21b) is 2 pressure small holes (17) (+
8) to the bellows internal chamber (6) and the bellows external chamber (7) via the pressure paths (+9) and (20), the above-mentioned pressure changes depending on the fluid flow rate in the bent pipe (15). The electrodeposited bellows (5) expands and contracts due to the differential pressure between the two sections (21δ) (21b), that is, the differential pressure between the bellows internal chamber (6) and the bellows external chamber (7). The electrodeposited bellows (5) is an extremely thin bellows-shaped member formed by a type of plating method, and can sense a small load (differential pressure) with high sensitivity and convert it into an amount of expansion and contraction. Differential transformer (
9) converts this amount of expansion and contraction into electric ψ, that is, alternating current is applied to the secondary coil (IOa) from a Tv source (not shown), and the secondary coils (job) on both sides of the primary coil (IOa)
(IOc).

'itf Different induced voltages are generated depending on the position of the core (11) that moves with the expansion and contraction of the R bellows (5), and the differential voltage is flattened by a rectifier circuit (not shown), etc.
It is converted into demons and output.

According to Example L? The bellows (5) are bent!
(+5) The differential transformer (9) expands and contracts by sensing a slight pressure difference between the curve outside portion (21a) and the curve inside portion (21b) within the curve.
The minute flow rate can be measured from the 711 force signal. In addition, the -1rt, s bellows (5), the cylinder containing it (1), and the differential transformer (9) can be very small, and therefore, conventional flowmeters using It can be made smaller compared to.

In addition to the differential transformer (9), as a detection means for detecting the amount of expansion and contraction of the electrodeposited bellows (5), for example, a magnet is provided on the movable side (electroplated bellows (5) side),
Various methods are possible, such as providing a magnetic resistance element on the cylinder (1) side.

〔Effect of the invention〕

As explained above, the flow meter of the present invention uses fluid! f& can be expressed as the differential pressure generated between the outside and inside of the curve when fluid passes through the curved pipe, and this can be expressed by using a highly sensitive bellows such as an electrodeposited bellows and the expansion/contraction field of the bellows electrically. It is characterized by the fact that it measures by means of detection, making it possible to measure minute amounts of hydrochloric acid.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a conventional example. (IOa) - Secondary coil (10b) (10c) Secondary fill (+1) Core (+5) Bent pipe (+8a) Curve outer wall (16b) Curve inner wall (+7) (Il
+) Small holes for pressure conduction (19) (20) Pressure conduction path Patent applicant Eagle T Gyo Co., Ltd.

Claims (1)

[Claims] 1. A cylinder having an interior hermetically divided into two chambers by a bellows, and a detection means for detecting the amount of expansion and contraction of the bellows,
The bellows internal chamber and the bellows external chamber in the cylinder communicate with a pair of small pressure guiding holes opened in the curved inner wall and curved outer wall of the curved pipe connected in the middle of the flow path, respectively. A flowmeter using a bellows. 2. A flowmeter using a bellows according to claim 1, wherein the bellows is an electrodeposited bellows.