KR0171633B1 - Flow meter having a contoured plug and resilient means - Google Patents

Abstract

The present invention relates to a flow meter, wherein the plug 12 can move relative to the orifice plate 8 against the resilience of the spring 20, which spring 20 supports the plug 12. Or the force applied to the support (26) or capsule (42) is sensed by the strain gage probu 30 or strain gage (44), the signal generated by the gage It is to be provided as a measure of the pressure drop or flow rate generated around the orifice plate (8).

Description

Flow rate

1 is a schematic view showing the inside of a flow meter according to the invention.

2 is a schematic view showing a modified embodiment of the flow meter shown in FIG.

* Explanation of symbols for main parts of the drawings

2: conduit 4: inlet

6: exit 8: orifice plate

10: opening 12: plug

14: horizontal axis 16: support member

18: annular pressure plate 20: spring

22: stopper 24: hole

26: support 28: external sensing system

30: strain probe 32: circuit

34: bellows 38, 40: pressure tapping

42: capsule 43: space

44 high temperature strain gauge 46 wire

48: tube

The present invention relates to a flow meter for measuring the flow rate of the flow rate, and more particularly to a flow meter that can accurately measure the flow rate without being affected by the pressure drop.

In general, the flowmeter is designed to operate on the principle that the force exerted on the body, which is held in the conduit through which the fluid flows, is related to the flow rate of the fluid, and the speed change around the body causes a pressure change, which is applied to the body. Losing traction results from the pressure difference between the upstream and downstream surfaces.

Conventional known flowmeters are attached to a support member extending out of the conduit and are provided with a traction plate which can pivot about the conduit around the support column, which is applied to the support member to support the support member. It is to measure the force to rotate about the support column.

Although such a flow meter is described in section 302.703 of British Standard BS 7405, there is a problem that the response is non-linear and the supporting column is easily damaged.

On the other hand, British Patent No. 1566251 discloses a differential pressure orifice plate flow meter, which is composed of a conduit having a constriction with a plug installed therein, the plug being elastic means by a pressure difference with respect to the constriction. It is provided to be movable in the axial direction with respect to the flow path cross-sectional area of the contraction portion, while the elastic means has a structure provided between the plug and the locking means.

Accordingly, an object of the present invention is to provide a flow meter having a measuring means adapted to generate a signal corresponding to the flow rate passing through the conduit according to the force applied by the elastic means caught by the locking means.

Flow meter of the present invention for achieving this object is a plug is installed on the horizontal axis extending in the longitudinal direction in the conduit, the locking means is composed of an annular member disposed on the horizontal axis. In addition, a stopper is provided to limit the axial movement of the locking means, the locking means is connected by the measuring means, the measuring means is disposed on both sides of the support and the strain to react according to the deformation of the support member It has a strain bridge with a probe.

On the other hand, as another embodiment of the present invention, the locking means is composed of a body having a chamber and the measuring element is installed in the chamber, the body is made of a cylindrical housing to surround the horizontal axis, the elastic member is one side of the body The structure is arranged adjacent to the soluble diaphragm forming the tip wall.

In addition, the measuring element is composed of a strain gauge that reacts according to the deformation of the diaphragm, and the strain gauge is preferably a high temperature compensation strain gauge.

Then, the connecting member extends from the sealed body to the outside of the conduit, and the connecting member has a wire for transmitting a signal from the measuring element. In particular, the plug is shaped such that a linear relationship can be established between the force applied to the plug and the flow rate through the interior of the conduit.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

The flow meter shown in FIG. 1 has a conduit 2 with an inlet 4 and an outlet 6 in which an orifice plate 8 with an opening 10 is fixed, the opening A conical plug 12 moving along the axial direction is provided so as to variably limit the size of 10.

The plug 12 is installed to move along the horizontal axis 14 fixed to the support member 16 installed in the conduit 2, and downstream of the plug 12 around the horizontal axis 14. An annular pressure plate 18 is installed, and a spring 20 is built in the axial direction between the plug 12 and the annular pressure plate 18 inside the conduit 2, and downstream of the annular pressure plate 18. The stopper 22 is fixed to the horizontal axis 14 is provided.

A hole 24 is formed in the wall of the conduit 2 corresponding to the installation point of the annular pressure plate 18 along the longitudinal direction of the conduit 2, and penetrates the hole 24 to allow the annular pressure plate 18 to pass through. A support 26 is installed from the radially outward to the external sensing system 28, the tip of which is remote from the annular pressure plate 18 of the support 26 fixed to the conduit 2; It is installed in a cantilevered form (not shown).

The external sensing system 28 is composed of two strain probes 30 which are located on opposite sides of the support 26 and form a strain bridge, and the signal output from the strain bridge is sent to the circuit 32. The input and amplified signal is then converted into a signal representing the flow rate flowing along the conduit 2.

Each element of the circuit 32 and the strain bridge are isolated from the inside of the conduit 2 by a bellows 34 which can receive the pressure inside the conduit 2 and can be easily bent even with a small resistance.

On the other hand, one side of the bellows 34 is connected to the support (26) is not extended.

In the use of the flow meter of the embodiment according to FIG. 1 having the structure as described above, the fluid enters the inlet 4 of the conduit 2 and flows freely towards the orifice plate 8, the conical plug 12. Since the opening 10 formed in the orifice plate 8 and the outer surface of the conduit 2 is variable, the fluid flowing from the inlet 4 side of the conduit 2 according to the flow rate of the fluid flowing along the inside of the conduit 2 The force is applied to the plug 12, which causes the plug 12 to slide along the horizontal axis 14, thereby increasing the size of the opening 10.

The movement of the plug 12 compresses the spring 20 while being resisted by the spring 20, and presses the annular pressure plate 18 again to the spring 20, in the case of steady flow. The plug 12 applies a predetermined force to the annular pressure plate 18 while reaching the parallel state.

This force causes the support 26 to bend, and the resulting bending strain is measured by a strain bridge consisting of strain probes 30. Then, the strain signal measured at this strain bridge is converted into the flow rate flowing from the external sensing system 28.

Thus, the flow rate is determined by the force exerted on the plug 12 by the fluid flowing regardless of the pressure drop occurring through the orifice plate 8, but if the pressure drop is to be known the circuit 32 Adjust to get this information from the strain gage sortie.

On the other hand, when the flow rate exceeds the system, the stopper 22 is provided to protect the annular pressure plate 18 since the force applied to the annular pressure plate is greater than the force expected from the normal operating state. This stopper 22 is intended to act as a locking means. However, the plug 12 can continue to move toward the annular pressure plate 18 by the pressing force of the spring 20, and by allowing the stopper 22 to transmit an overload to the support 26, 26) shall not be damaged.

2 shows another embodiment of the present invention, in which the same parts as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 1, the plug 12 is installed on the horizontal axis 14 so as to be movable, and the plug 12 variably limits the opening area of the opening 10 formed in the orifice plate 8. A spring 20 is provided along the axial direction between the plug 12 in the conduit 2 and the annular pressure plate 18.

In this FIG. 2, the flow measurement system consists of a capsule 42 installed around the horizontal axis 14, which is a conical curved surface, that is, a cylindrical annulus. Therefore, the capsule 42 has a sealed structure having a space 43 therein, and is provided with a catching means for catching the spring 20 so that one side of the capsule serving as the annular pressure plate 18 is It consists of a diaphragm, and on the opposite side where the spring 20 of the annular pressure plate 18 is installed, a plurality of high temperature strain gauges 44 are provided, for example four compensation gauges.

The capsule 42 is filled with a medium capable of operating even at high temperatures. The medium can be made of, for example, an inert gas, vacuum, air or plastic material.

The wire 46 extending from the gauge 44 extends out of the conduit 2 through the metal tubing 48, and the wire 46 inserted into the tube 48 is sealed to form a capsule ( 42) The media inside is prevented from leaking.

And the position of the capsule 42 is determined by the stopper 22, the stopper 22 is the spring 20 is caught and the elastic force of the capsule 42 by the pressing force of the spring 20 The locking means to support is achieved.

The flow meter shown in FIG. 2 operates on the same principle as shown in FIG. 1, but only the flow meter in FIG. 2 does not move the capsule 42, resulting in the tube 48 being drawn out of the conduit 2 The structure required to penetrate is not complicated.

The force exerted on the annular pressure plate 18 by the spring 20 causes the annular pressure plate 18 to bend, but instead the capsule 42 remains in a fixed position while the system is operating. This deformation of the annular pressure plate 18 is sensed by the strain gauge 44, which generates a signal corresponding to the applied load.

This signal is sent to an external sensing system (not shown) through a wire 46 installed in the tube 48, so that the resulting strain signal is directly related to the flow of fluid flowing along the inside of the conduit 2 You lose.

However, the flow meter shown in FIG. 2 can obtain additional effects by using the capsule 42. For example, by installing a pressure measuring means in the capsule 42, the static pressure can be measured. By installing a temperature sensor, a temperature measuring means can be provided for density compensation. Therefore, the capsule 42 is to provide a means for measuring the true flow amount, including temperature and density compensation.

In the two embodiments, the conical plug 12 is preferably shaped specifically to allow a linear relationship between the flow rate flowing inside the conduit 2 and the strain meter to simplify the measurement, In addition, the conical plug design and the opening 10 formed in the orifice plate can form a flow meter capable of measuring a wide range of moving flow rates, while linearly between the pressure drop and the flow rate generated when passing through the flow meter. It is desirable to have a relationship.

On the other hand, the pressure tapping (38, 40) is provided at the front and rear ends of the conduit (2), respectively, so that the measurement state of the flow meter can be checked without disturbing the internal parts of the flow meter, and the fluid passes through the flow meter. A differential pressure transducer can be connected between both tappings 38 and 40 to compare the results read here and the output of the circuit 32 with the original manufacturing measurements to determine whether the flowmeter continues to operate normally.

Claims (15)

Consisting of a conduit 2 having an orifice plate 8 with a plug 12 seated thereon, the plug 12 being moved axially against the resilient means by a pressure difference between the front and back of the orifice plate 8. It is installed so as to vary the fluid passage and cross-sectional area of the orifice plate (8), the elastic means is installed between the plug 12 and the locking means, while the external sensing system 28 is provided in the conduit (2) Characterized in that the external sensing system (28) is adapted to generate a signal indicative of the flow rate flowing inside the conduit (2) while reacting according to the force exerted by the resilient means caught on the locking means. Flow meter. 2. A flow meter according to claim 1, characterized in that a plug (12) adapted to move along the axial direction is provided on a transverse axis (14) extending longitudinally in the conduit (2). The flow meter according to claim 1 or 2, wherein the elastic means is made of a spring (20). 2. The plug 12 according to claim 1, characterized in that the plug 12 is shaped such that the relationship between the force exerted on the plug 12 and the flow rate flowing along the interior of the conduit 2 is linearly proportional. Flow meter. 2. A flow meter according to claim 1, wherein said locking means consists of an annular pressure plate (18) arranged around a horizontal axis (14). 6. A flow meter according to claim 5, characterized in that a stopper (22) is provided on the horizontal axis (14) for limiting the axial movement of the annular pressure plate (18). 7. Flowmeter according to claim 6, characterized in that the annular pressure plate (18) is connected to the sensing system (28) by a support (26) extending through a hole (28) formed in the wall of the conduit (2). 8. A flow meter according to claim 7, characterized in that the tip located away from the annular pressure plate (18) of the support (26) is fixed to the conduit (2). A flow meter according to claim 1, characterized in that the external sensing system (28) is adapted to react according to the deformation of the support (26) with respect to the conduit (2). 10. The flow meter of claim 9, wherein the external sensing system (28) consists of a strain bridge consisting of a plurality of strain probes (30) disposed on opposite sides of the support (26). The flow meter according to claim 1, wherein the locking means is made of a capsule (42) having a space (43), and a plurality of measuring elements are arranged in the space (43). An elastic means for an annular pressure plate (18) according to claim 11, wherein said capsule (42) is composed of an annular cylindrical housing provided on a horizontal axis (14), and made of a flexible diaphragm forming a tip wall of said capsule (42). Flowmeter characterized in that the hanging. 12. The flow meter of claim 11 wherein the measuring element comprises a strain gauge that reacts as the diaphragm deforms. 14. The flow meter of claim 13 wherein the measurement element consists of four high temperature compensated strain gauges. 12. The tube (48) according to claim 11, wherein a tubing (48) is connected from the capsule (42) to the outside of the conduit (2), and in this tube (48) a wire (46) for transmitting a signal from the measuring element is provided. Flow meter, characterized in that installed.