KR101941423B1 - Apparatus for monitoring leakage rate in pipes by using laminar flow element - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage rate monitoring apparatus for measuring and monitoring a leakage rate occurring in a piping installed in a facility such as a nuclear power plant. The leakage rate monitoring apparatus includes: a gas inlet through which gas flows; A flow rate measuring unit connected to the gas inlet and branching to a plurality of flow channels and having different flow measurement ranges for each flow channel; A gas outlet connected to the gas inlet to discharge the gas; A control unit for controlling the operation of the flow measuring unit; Wherein the flow rate measuring unit comprises: an input unit into which gas flows; An output section through which gas flows; A plurality of said passages connected between said input section and said output section; A valve for opening and closing the plurality of flow paths, respectively; A differential pressure meter for measuring a differential pressure between the input unit and the output unit; And at least one laminar flow element having a predetermined diameter and a length and capable of passing a gas therethrough is provided in the plurality of flow paths, and the gas introduced into the flow path can flow only through the laminar flow element.
According to this configuration, by replacing the sensor for measuring the leak rate with the laminar flow element, it is possible to provide a leak rate monitoring apparatus in which the weight of the product is reduced and the movement is easy and the accuracy of leak rate measurement can be maintained even for a long time .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for monitoring leakage rate using a laminar flow element,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage rate monitoring apparatus for measuring and monitoring a leakage rate occurring in a piping installed in a facility such as a nuclear power plant.

Facilities such as nuclear power plants are equipped with a number of piping, which are equipped with valves for fluid movement. Measuring and monitoring fluid leakage and leakage through valves or piping is critical to the safety of the facility.

To measure the leakage, completely close the valves at the front and rear of the piping and measure the leakage between the valve and the valve. To do this, first supply the compressed air to the piping through the leak rate monitoring device, and wait until the pressure inside the piping is stabilized. Next, while the compressed air is further supplied to the piping, the amount of air supplied to the piping is measured to determine the degree of leakage.

Leakage in piping can be detected from the outside, and in most cases leakage occurs mainly on the valve seat rather than on the piping. If the leak amount is measured and the leakage amount is larger than the allowable value, the valve is repaired or replaced.

In the conventional leak rate monitoring apparatus, a plurality of mass flow meters are installed for each capacity in order to measure leaked flow rate.

The operator carries the leak rate monitoring device and measures the leakage amount per pipe, which weighs about 18 kg, and the weight of the mass flowmeter is about 7 kg. Therefore, if the weight of the mass flow meter is reduced in the leak rate monitoring apparatus, it is possible to solve the difficulty of the operator repeatedly carrying out the test.

Also, when the mass flowmeter is used for a long time, the measurement value of the mass flowmeter as the sensor is changed, and the operator has a problem that the accuracy of the leak rate measurement is lowered while correcting the electrical signal of the mass flowmeter.

Korea Patent No. 10-0526291

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for measuring leakage rate by replacing a sensor for measuring leak rate with a laminar flow element, And an object of the present invention is to provide a leakage rate monitoring apparatus.

In order to accomplish the above object, there is provided a leakage rate monitoring apparatus for monitoring a leakage rate by injecting gas according to the present invention, comprising: a gas inlet through which gas flows; A flow rate measuring unit connected to the gas inlet and branching to a plurality of flow channels and having different flow measurement ranges for each flow channel; A gas outlet connected to the gas inlet to discharge the gas; A control unit for controlling the operation of the flow measuring unit; Wherein the flow rate measuring unit comprises: an input unit into which gas flows; An output section through which gas flows; A plurality of said passages connected between said input section and said output section; A valve for opening and closing the plurality of flow paths, respectively; A differential pressure meter for measuring a differential pressure between the input unit and the output unit; And at least one laminar flow element having a predetermined diameter and a length and capable of passing a gas therethrough is provided in the plurality of flow paths, and the gas introduced into the flow path can flow only through the laminar flow element.

The plurality of flow paths each include a support plate for supporting the laminar flow element in the flow path, wherein an opening is formed in the support plate, and in a state in which the laminar flow element is inserted through the opening, Is welded.

The plurality of flow paths may include a first flow path on one side of the support plate and a second flow path on the other side of the support plate. In a state where the laminar flow elements are inserted into the first flow path and the second flow path, And the flow path and the second flow path are brought into contact with the support plate to be welded.

A leak rate monitoring device including a gas inlet, a gas outlet, a flow rate measuring unit branched from the plurality of flow channels and having different flow rate measurement ranges for each flow rate, and a control unit for controlling the operation of the flow rate measuring unit, A method of monitoring a leak rate of a measurement object using a gas outlet includes connecting the gas inlet to a gas source and supplying a gas supplied through the gas outlet to the measurement object through the gas outlet; Supplying a gas supplied through the gas source to a measurement object through a flow path having a widest measurement range of the flow measurement unit; Supplying a gas supplied through the gas source to a measurement object through a flow path having a next broad measurement range of the flow measurement unit; Wherein at least one laminar flow element having a predetermined diameter and a predetermined length and capable of passing gas therethrough is provided in the flow path, the gas introduced into the flow path can flow only through the laminar flow element, The controller monitors the flow rate of the gas flowing through the flow path and the leakage rate of the measurement object from the pressure difference across the laminar flow element.

Further, the laminar flow element is inserted through an opening formed in the support plate and supported by the flow path, and the opening is welded between the circumference of the laminar flow element.

According to the present invention, it is possible to provide a leakage rate monitoring apparatus which can reduce the weight of a product and is convenient to move and can maintain the accuracy of leakage rate measurement even for a long period of time by replacing a sensor for measuring leak rate with a laminar flow element .

1 is a view for explaining a method of measuring a leakage amount through a valve using the leakage rate monitoring apparatus of the present invention.
2 is a view for explaining a method for measuring a leakage rate in the leakage rate monitoring apparatus of the present invention.
3 is a diagram showing a configuration of a leakage rate monitoring apparatus according to an embodiment of the present invention.
FIG. 4 is a view for explaining the configuration of the flow rate measuring unit in detail in FIG.
5A to 5F are views for sequentially illustrating a method of supporting the laminar flow element of the present invention on a flow path.
6 is a graph showing an experimental example in which the flow rate is measured through the flow rate measuring unit of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The same reference numerals in the drawings denote like elements throughout the drawings.

1 is a view for explaining a method of measuring a leakage amount through a valve using the leakage rate monitoring apparatus of the present invention. 2 is a view for explaining a method for measuring a leakage rate in the leakage rate monitoring apparatus of the present invention. 3 is a diagram showing a configuration of a leakage rate monitoring apparatus according to an embodiment of the present invention. FIG. 4 is a view for explaining the configuration of the flow rate measuring unit in detail in FIG.

The leakage rate monitoring apparatus 100 of the present invention includes a gas inlet 101, a flow rate measuring unit, a gas outlet 102, a controller 160, a display unit 170, and the like.

The gas inlet 101 is connected to a gas source, and a compressed gas from the gas source is introduced.

The flow rate measuring unit is connected to the gas inlet 101 and branched into a plurality of flow paths, and has different flow measurement ranges for each flow path. A filter 110 is disposed at the front end of the flow measuring section to filter moisture or fine dust that may be present in the gas. After the filter 110, a regulator 120 for controlling the pressure of the introduced gas may be disposed.

The gas outlet 102 is connected to the gas inlet 101 to discharge the gas and the gas outlet 102 is connected to the pipe 10 or the like for measuring the leak rate. The gas outlet 102 is provided with a valve 102a for opening and closing the flow passage. A vent channel 103 for discharging gas to the outside can be disposed separately from the gas outlet 102 and a valve 103a for opening and closing the channel is disposed in the vent channel 103. [

The control unit 160 controls the operation of the flow rate measuring unit and the like. The display unit 170 displays a process of measuring the leak rate on the screen.

In order to measure the leakage rate of the piping 10, the gas inlet 101 of the leakage rate monitoring apparatus 100 is connected to the gas source. The compressed gas supplied from the gas source is supplied to the piping 10 through the gas inlet 101, the connecting pipe 145 and the gas outlet 102 while the valve 20 of the piping 10 is closed. It is possible to monitor the leakage rate in the pipe 10 while supplying the gas through the plurality of flow paths 141, 142, 143, and 144 of the flow rate measuring unit in a state where the pressure in the pipe 10 is stable.

The flow rate measuring unit includes an input unit 130, an output unit 150, a plurality of flow paths 141, 142, 143 and 144, valves 131, 132, 133 and 134,

The gas is introduced into the input unit 130. The gas flowing into the input unit 130 flows out to the output unit 150 through any one of the plurality of flow paths 141, 142, 143, and 144. The gas discharged to the output unit 150 may be supplied to the pipe 10 through the gas outlet 102.

A plurality of flow paths 141, 142, 143 and 144 are connected between the input section 130 and the output section 150 and valves 131 and 132 for opening and closing the flow paths are connected to the flow paths 141, 132, 133, and 134 are disposed. The valves 131, 132, 133 and 134 are installed individually in the respective flow paths 141, 142, 143 and 144, but one valve for selectively opening and closing the respective flow paths may be provided.

The differential pressure gauge 155 measures a differential pressure between the input unit 130 and the output unit 150. A temperature sensor 104 may be installed in the input unit 130 and a pressure sensor 105 may be installed in the output unit 150. The position where the temperature sensor 104 and the pressure sensor 105 are installed can be changed.

At least one laminar flow element having a predetermined diameter and length and capable of passing gas is provided in the plurality of flow paths 141, 142, 143, and 144. The gas introduced into the flow paths 141, 142, 143 and 144 is configured to flow only through the laminar flow element.

Referring to FIG. 2, the differential pressure and the flow rate Q can be obtained from the following equation when the gas flows in the inside of the tubular section and the flow velocity is low in the laminar flow region (for example, when the Reynolds number is 2300 or less).

^{Q = (πD 4 / 128μL)} * △ P formula (1)

Here, Q is the flow rate, D is the diameter of the flow path, mu is the viscosity of the fluid, L is the length of the flow path, and DELTA P is the pressure difference between the front end and the rear end of the flow path.

Referring to Fig. 4, the plurality of flow paths 141, 142, 143, and 144 each include a support plate for supporting the laminar flow elements in the flow path.

For example, the flow path 141 includes one laminar flow element 141b having a diameter of 0.25 mm and a length of 85 mm, and the laminar flow element 141b is supported on the flow path 141 through the support plate 141a. The flow path 141 can measure a flow rate of 2 to 20 ccm (cm ³ / min).

The flow path 142 includes two laminar flow devices 142b each having a diameter of 0.25 mm and a length of 85 mm and the laminar flow devices 142b are supported on the flow path 142 through the support plate 142a. The flow path 142 can measure the flow rate of 20 to 200 ccm.

The flow path 143 includes two laminar flow devices 143b each having a diameter of 0.54 mm and a length of 85 mm and the laminar flow devices 143b are supported by the flow path 143 through the support plate 143a. The flow path 143 can measure a flow rate of 200 to 2000 ccm.

The flow path 144 includes 20 laminar flow devices 144b having a diameter of 0.54 mm and a length of 85 mm and the laminar flow devices 144b are supported on the flow path 144 through the support plate 144a. The flow path 144 can measure the flow rate of 2000 to 20,000 ccm.

5A to 5F are views for sequentially illustrating a method of supporting the laminar flow element of the present invention on a flow path.

Referring to FIG. 5A, a support plate 142a having an opening 142a 'is provided. The support plate 142a is formed of a circular thin plate, and the diameter of the support plate 142a is formed larger than the diameter of the flow path.

Referring to FIG. 5B, a laminar flow element 142b is inserted through the opening 142a '. The laminar flow elements 142b are formed in two and each may have a diameter of 0.25 mm.

Referring to FIG. 5C, the space between the opening 142a 'and the circumference of the laminar flow element 142b is welded (P1). This prevents the gas from leaking through the space between the opening 142a 'and the laminar flow element 142b.

5D, a first flow path 142c is disposed on one side of the support plate 142a, and a second flow path 142d is disposed on the other side of the support plate 142a. At this time, the laminar flow element 142b is inserted into the first flow path 142c and the second flow path 142d.

Referring to FIG. 5E, the first flow path 142c and the second flow path 142d are brought into contact with the support plate 142a.

Referring to FIG. 5F, welding P2 is performed between the first flow path 142c and the support plate 142a and between the second flow path 142d and the support plate 142a.

Referring again to FIG. 4, the gas flowing through the flow paths 141, 142, 143, and 144 flows only into the laminar flow devices 141b, 142b, 143b, and 144b. This is because the circumference of the laminar flow element and the support plate are welded, and the flow path and the support plate are also welded.

In the case where a plurality of (for example, 20) laminar flow devices 144b such as the flow path 144 are disposed, one opening is formed in the support plate 144a, and 20 laminar flow devices 144b are formed through this opening. Can be inserted. Next, the gap between the opening and the laminar flow element 144b and between the laminar flow elements 142b may be welded so that the gas flows only into the laminar flow element 144b.

According to the leak rate monitoring apparatus (100) of the present invention, the laminar flow devices (141b, 142b, 143b, 144b) are disposed in a flow rate measuring unit branched from a plurality of flow paths and having different flow measurement ranges for each flow path, The differential pressure at both ends of the valves 141b, 142b, 143b, and 144b is measured to measure the leak rate.

Such a flow rate measuring unit has a very simple structure and a small number of parts, thereby reducing the weight of the leak rate monitoring apparatus 100. Accordingly, there is an advantage that the operator who moves the leak rate monitoring apparatus 100 while monitoring the leakage rate for each pipe is convenient to move.

In addition, since such a flow rate measuring unit has a simple structure and has a small measurement error, it can be easily and inexpensively replaced, so that the measurement accuracy of the leak rate monitoring apparatus 100 can be maintained even for a long time.

Hereinafter, a method of monitoring the leakage rate of a measurement object using the leakage rate monitoring apparatus 100 of the present invention will be described with reference to FIGS. 1 to 4. FIG.

First, the gas inlet 101 of the leakage rate monitoring apparatus 100 is connected to a gas source, and the gas supplied through the gas source is connected to the measurement object (for example, , Piping). After a predetermined time, the pressure inside the pipe becomes constant. At this time, only the valve 135 is opened and the remaining valves 131, 132, 133 and 134 are closed.

Next, the gas supplied through the gas source is supplied to the pipe through the flow path having the widest measuring range of the flow rate measuring section. In this embodiment, the gas is supplied through the flow path 144 capable of measuring the flow rate of 2,000 to 20,000 ccm. At this time, only the valve 134 is opened and the remaining valves 131, 132, 133 and 135 are closed.

The controller 160 monitors the flow rate of the gas flowing through the flow path 144 and the leak rate of the measurement object from the pressure difference across the laminar flow element 144b.

Next, when it is judged that there is no leakage, the gas supplied through the gas source is supplied to the pipe through the flow path having the next widest measuring range of the flow measuring portion. In this embodiment, the gas is supplied through the flow path 143 capable of measuring a flow rate of 200 to 2000 ccm. At this time, only the valve 133 is opened and the remaining valves 131, 132, 134 and 135 are closed. In this manner, the gas is sequentially supplied through the flow path 142 and the flow path 141 to monitor the flow rate of the gas and the leak rate of the measurement object.

According to the method of monitoring the leakage rate of the measurement object, the leakage rate of the measurement object can be determined very simply and accurately.

6 is a graph showing an experimental example in which the flow rate is measured through the flow rate measuring unit of the present invention. The relation between flow and differential pressure in the tubule is applied in the fully developed region, and when the length of the tubule is short, there is an entrance effect in which the flow is not developed and the correlation between the pressure difference and the flow rate is experimentally constructed Respectively.

This experiment was conducted in a flow path capable of measuring a flow rate of 200 to 2000 ccm using two laminar flow devices having a diameter of 0.54 mm and a length of 85 mm. The supplied gas can be measured with air, and the temperature and pressure can be measured to determine the viscosity of the air. The passage pressure is about 49 psi, and the differential pressure is about 500 to 4000 Pa.

The theoretical flow rate obtained in equation (1) is indicated by the lower straight line, and the actually measured flow rate is indicated by the dotted line. When actually measuring the leakage amount, the flow rate can be obtained by substituting the differential pressure measured by the differential pressure gauge 155 into the graph obtained by the experiment. Such a flow rate may be a leakage amount in the pipe.

A graph is obtained by experiment for each laminar flow element provided in the flow rate measuring unit, and the controller 160 can calculate the leakage amount from the differential pressure and display it on the display unit 170. [

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: Leakage rate monitoring device
101: gas inlet
102: gas outlet
103: Vent flow
104: Temperature sensor
105: Pressure sensor
110: filter
120:
130:
131, 132, 133, 134, 135: valve
141, 142, 143, 144:
142a:
142b: Laminar flow element
142c:
142d:
145: Connector
150:
155: Differential pressure gauge
160:
170:

Claims (5)

1. A leak rate monitoring apparatus for monitoring a leak rate by inputting gas, comprising:
A gas inlet through which gas flows;
A flow rate measuring unit connected to the gas inlet and branching to a plurality of flow channels and having different flow measurement ranges for each flow channel;
A gas outlet connected to the gas inlet to discharge the gas;
A control unit for controlling the operation of the flow measuring unit;
Lt; / RTI >
Wherein the flow-
An inlet through which gas flows;
An output section through which gas flows;
A plurality of said passages connected between said input section and said output section;
A valve for opening and closing the plurality of flow paths, respectively;
A differential pressure meter for measuring a differential pressure between the input unit and the output unit;
Lt; / RTI >
Wherein at least one laminar flow element having a predetermined diameter and a length and capable of passing gas therethrough is provided in each of the plurality of flow paths, the gas introduced into the flow path can flow only through the laminar flow element,
Wherein the flow rate measuring unit has different flow measurement ranges for each flow channel by making the diameters of the laminar flow devices or the number of the laminar flow devices different from each other in each of the flow paths. The method according to claim 1,
The plurality of flow paths each include a support plate for supporting the laminar flow element in the flow path,
Wherein an opening is formed in the support plate and the opening is welded between the circumference of the laminar flow element with the laminar flow element inserted through the opening. 3. The method of claim 2,
Wherein each of the plurality of flow paths includes a first flow path on one side of the support plate and a second flow path on the other side of the support plate, and in a state in which the laminar flow element is inserted into the first flow path and the second flow path, And the second flow path is in contact with the support plate to weld the second flow path. A leakage rate monitoring device including a gas inlet, a gas outlet, a flow rate measuring unit branched from a plurality of flow paths and having different flow measurement ranges for each flow rate, and a control unit for controlling the operation of the flow rate measuring unit, A method for monitoring leakage rate,
Connecting the gas inlet to a gas source and supplying the gas supplied through the gas source to the measurement object through the gas outlet;
Supplying a gas supplied through the gas source to a measurement object through a flow path having a widest measurement range of the flow measurement unit;
Supplying a gas supplied through the gas source to a measurement object through a flow path having a next broad measurement range of the flow measurement unit;
Lt; / RTI >
Wherein at least one laminar flow element having a predetermined diameter and a length and capable of passing gas therethrough is provided in the inside of the flow path and the gas introduced into the flow path can flow only through the laminar flow element,
The diameter of the laminar flow element or the number of the laminar flow elements is different in each of the flow paths,
Wherein the controller monitors a flow rate of a gas flowing through the flow path and a leakage rate of a measurement object from a pressure difference between both ends of the laminar flow element. 5. The method of claim 4,
Wherein the laminar flow element is inserted through an opening formed in the support plate and is supported by the flow path, and the leakage between the opening and the circumference of the laminar flow element is monitored.

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