KR20180026002A - Active noise control applied fouling preventing system of heat exchanger - Google Patents

Abstract

The present invention relates to a fouling reduction system of a heat exchanger with an active noise control applied. According to the present invention, the fouling reduction system of the heat exchanger with the active noise control applied comprises: a tank which comprises: an inlet through which a working fluid is introduced; and an outlet through which the working fluid is discharged; a heat-exchanging pipe placed in the tank to exchange heat with the working fluid; a plasma generation unit to generate plasma spark on the heat-exchanging pipe; a flow meter installed on an entrance of the heat-exchanging pipe to measure flux; a first sensor to measure the physical quantity at the entrance and exit of the heat-exchanging pipe; a second sensor to measure vibrations of the heat-exchanging pipe; a control unit to determine if a fouling occurs by comparing data of the entrance and exit of the heat-exchanging pipe measured by the first sensor with reference data for generating plasma spark, which are calculated through a computational fluid dynamics analysis, to generate a plasma spark generation signal, and to output an excitation signal by entering a vibration signal measured by the second sensor, thereby performing active noise control; and an excitation means to excite in accordance with the excitation signal. The present invention is to provide a control system to precisely determine if a fouling is formed in the heat-exchanging pipe.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an active noise control system for a fouling preventing system,

The present invention relates to a system for reducing fouling in a heat exchanger to which active noise control is applied, and more particularly, to a system and method for reducing the fouling of a heat exchanger using a plasma generated by a computational fluid dynamics analysis A determination is made as to whether or not fouling has occurred through comparison of reference data for generating a spark, a plasma spark generation signal is generated to reduce the formation of fouling in the heat exchange pipe of the heat exchanger, And to a system for reducing fouls in a heat exchanger in which active noise control is performed by generating an anti-phase signal with respect to a measured vibration signal to perform active noise control.

Generally, the heat exchanger for hot water generation is known to be reduced by 50 ~ 90% heat transfer compared to the initial heat exchanger by fouling after about 5 years of installation.

In particular, the heat storage tank used in the solar heat collection system or the heat pump water heater using the antifreeze has a large temperature difference due to heat exchange with the water in the storage tank through the heat exchanger and the hot water flow in the storage tank is considerably small, Ring formation is known to be more severe.

In order to suppress the formation of the fouling of the heat exchanger, a method using mechanical washing or chemical is conventionally used. However, there is a problem that the mechanical washing requires a lot of working time and a stoppage of the heat exchanger in addition to the troublesome operation.

In addition, the method using a chemical has a problem that the heat exchange efficiency of the heat exchanger is lowered due to an undesirable side reaction in the heat exchanger.

On the other hand, a method of continuously generating a plasma spark at a predetermined time interval in the heat exchange pipe of the heat exchanger to reduce the formation of fouling has been proposed.

However, the plasma spark continuously applied to the heat exchange pipe to reduce the fouling formation accelerates the deterioration of the heat exchange pipe and shortens the life of the heat exchanger. In addition, vibration and noise are accompanied by the generation of plasma spark, and it is urgently required to develop a more environmentally friendly fouling reduction system.

Korean Patent Publication No. 2006-0040605

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control system for accurately determining whether or not a heat exchange pipe is fouled.

Another object of the present invention is to provide a control system for generating a plasma spark only when a fouling is formed on a heat exchange pipe at a predetermined reference value or more.

The present invention also aims to adjust the voltage of the plasma spark in proportion to the degree of fouling formed in the heat exchange pipe.

Another object of the present invention is to provide a fouling reduction system that reduces vibration and noise generated by a plasma spark.

The present invention relates to a tank having an inlet through which a working fluid flows and an outlet through which a working fluid flows, A heat exchange pipe disposed in the tank and performing heat transfer with the working fluid; A plasma generator for generating a plasma spark in the heat exchange pipe; A flow meter installed at an inlet of the heat exchange pipe to measure a flow rate; A first sensor for measuring a physical quantity of an inlet and an outlet of the heat exchange pipe; A second sensor for measuring vibration of the heat exchange pipe; And a controller for determining whether or not the fouling occurs by comparing the data of the inlet and the outlet of the pipe for heat exchange measured from the first sensor with the reference data for generating plasma sparks through computational fluid dynamics analysis, A control unit for generating active signals and outputting a signal having a vibration signal measured by the second sensor as an input, thereby performing active noise control; And an exciting means for exciting the excitation signal in accordance with the excitation signal. The present invention also provides a system for reducing fouls in a heat exchanger to which active noise control is applied.

Further, the vibration sensor of the present invention is characterized by being an accelerometer.

Further, the exciting means of the present invention is characterized by being an actuator.

Also, the excitation signal of the present invention is an excitation signal having an opposite phase to the vibration signal measured by the second sensor.

Further, the excitation signal of the present invention is characterized in that a time delay until a signal measured by the second sensor reaches the excitation means is applied.

Further, the sensors of the present invention may be a pressure gauge which is formed in a pair and measures the pressure at the inlet and the outlet of the heat exchange pipe.

Further, the sensors of the present invention may be a pair of thermometers for measuring the temperature of the inlet and the outlet of the heat exchange pipe.

The control unit of the present invention further includes a control unit for controlling the plasma spark generation signal when the pressure drop amount calculated based on the pressure data obtained by the pair of pressure gauges is larger than the reference data for generating the plasma spark calculated through the flow analysis (Computational Fluid Dynamics Analysis) .

Further, the control unit of the present invention may further include a plasma spark generation signal when the temperature difference calculated based on the temperature data obtained by the pair of thermometers is smaller than the reference data for plasma spark generation calculated through a flow analysis (Computational Fluid Dynamics Analysis) .

The plasma generating portion of the present invention includes an electrode for generating a plasma spark; A power supply connected to the electrode to supply current to the electrode; A grounding portion connected to the heat exchange pipe; A spark gap coupled between the power supply and the electrode; And a capacitor connected between the spark gap and the power supply.

The instantaneous voltage at the time of generating the plasma spark by the plasma generator of the present invention is 25 to 35 kV.

The present invention is characterized in that the distance between the heat exchange pipe and the electrode is 1 to 10 mm.

The control unit of the present invention is characterized in that the voltage of the plasma spark generation signal is increased in proportion to the pressure drop amount or the temperature difference.

The control unit of the present invention is characterized in that the duration of the plasma spark generation signal is increased in proportion to the pressure drop amount or the temperature difference.

The fouling reduction system of the heat exchanger according to the present invention has the effect of determining whether or not the fouling is formed without checking the pipe for the heat exchanger with the naked eye.

Also, the fouling reduction system of the heat exchanger according to the present invention has the effect of suppressing the occurrence of unnecessary plasma sparks and extending the life of the heat exchanger by generating plasma sparks only when the fouling is formed over a predetermined reference.

Further, the fouling reduction system of the heat exchanger according to the present invention has the effect of reducing the vibration and noise generated by the plasma spark.

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

1 is a block diagram of a fouling reduction system of a heat exchanger to which active noise control according to the present invention is applied.
2 is a conceptual diagram illustrating the principle of active noise control according to an embodiment of the present invention.

Hereinafter, various embodiments of the present document will be described with reference to the accompanying drawings. It should be understood, however, that the techniques described herein are not intended to be limited to any particular embodiment, but rather include various modifications, equivalents, and / or alternatives of the embodiments of this document. In connection with the description of the drawings, like reference numerals may be used for similar components.

Also, the terms "first," "second," and the like used in the present document can be used to denote various components in any order and / or importance, and to distinguish one component from another But is not limited to those components. For example, 'first part' and 'second part' may represent different parts, regardless of order or importance. For example, without departing from the scope of the rights described in this document, the first component can be named as the second component, and similarly the second component can also be named as the first component.

It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the other embodiments. The singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art. The general predefined terms used in this document may be interpreted in the same or similar sense as the contextual meanings of the related art and, unless expressly defined in this document, include ideally or excessively formal meanings . In some cases, even the terms defined in this document can not be construed as excluding the embodiments of this document.

1 is a block diagram of a fouling reduction system of a heat exchanger to which active noise control according to the present invention is applied.

1, a system for reducing fouling of a heat exchanger to which active noise control according to the present invention is applied includes a tank 200, a heat exchange pipe 100, a plasma generator 300, a flow meter 410, 1 sensor 420, a second sensor 430, a control unit 500, and a vibrating means 600.

The tank 200 is a part where heat exchange is performed. That is, the tank 200 is formed in a cylindrical shape having an inlet 210 and an outlet 230 so as to have a circulation structure in which a working fluid is introduced into the tank 200 and then discharged. A heat exchange pipe 100 is installed inside the tank 200 for heat transfer with the working fluid. Here, the heat exchange pipe 100 may have a structure in which the copper pipe is formed in a coil shape, but the present invention is not limited thereto, and the material and shape of the heat exchange pipe 100 may be changed to increase heat transfer efficiency . The heat exchange pipe 100 is provided with a heater for supplying high temperature fluid heated inside the heat exchange pipe 100 and a pump for circulating the high temperature fluid inside the heat exchange pipe 100 May be provided.

The plasma generating part 300 generates a plasma spark on the outer surface of the heat exchange pipe 100 inside the tank 200 to suppress fouling on the outer surface of the heat exchange pipe 100.

The plasma generating unit 300 includes an electrode 310, a power supply 320, a ground unit 330, a spark gap 340, and a capacitor 350.

The electrode 310 generates a plasma spark together with the heat exchange pipe 100. The electrode 310 is disposed inside the tank 200 and becomes a (+) electrode electrically connected to the power supply 320 through a cable. At this time, one end of the electrode 310 is spaced apart from the outer surface of the heat exchange pipe 100, and one end of the electrode 310 facing the heat exchange pipe 100 is formed to have a sharp conical shape do. Here, the interval between one end of the electrode 310 and the outer surface of the heat exchange pipe 100 is 1 to 10 mm. When the distance between the one end of the electrode 310 and the outer surface of the heat exchange pipe 100 is less than 1 mm, the electricity is directly transmitted to prevent the plasma spark from occurring, If the distance between the outer surface of the pipe 100 is larger than 10 mm, a corona-type plasma spark is generated, and a strong spark necessary for suppressing fouling is not generated.

The power supply 320 supplies a current to the electrode 310. The power supply 320 is electrically connected to the electrode 310 through a cable. It is preferable that the power supply 320 has an instantaneous voltage of 20 to 40 kV when a plasma spark occurs between the outer surface of the heat exchange pipe 100 and the electrode 310. However, But may be selectively applied depending on the diameter, length, and material of the material.

The grounding part 330 is a (-) electrode part electrically connected to the heat exchange pipe 100 through a cable.

The spark gap 340 is electrically connected between the electrode 310 and the power supply 320 through a cable. This spark gap 340 temporarily stores electricity to generate a plasma spark. That is, the spark gap 340 stores electricity as a rechargeable battery, and instantaneously generates a high voltage.

The capacitor 350 is electrically connected between the spark gap 340 and the power supply 320 through a cable. The capacitor 350 accumulates the electricity supplied from the power supply 320 and cuts off the direct current and allows the alternating current to be transmitted to the electrode 310.

A flow meter 410 is mounted at the inlet of the heat exchange pipe 100 to measure the flow rate of the fluid flowing inside the heat exchange pipe 100.

A plurality of first sensors 420 are mounted to obtain data on fouling formation. The first sensor 400 measures the physical quantity of the inlet and the outlet of the heat exchange pipe 100.

The first sensor 420 is equipped with a pressure gauge 421 for measuring the pressure at the inlet and outlet of the heat exchange pipe 100 at the inlet and the outlet.

In addition, a thermometer 423 for measuring the temperature at the inlet and the outlet is mounted at the inlet and the outlet of the heat exchange pipe 100.

The controller 500 determines whether or not a foul is formed, and provides a plasma spark generation signal to the plasma generator.

When the fouling is formed on the heat exchange pipe 100, the heat transfer efficiency through the pipe is lowered and the pressure drop amount through the pipe is increased.

Whether or not the fouling is formed is determined by using the phenomenon at the time of forming the fouling.

In the present invention, it is determined that the fouling is formed when the temperature difference calculated by the thermometer 423 installed at the inlet and outlet of the heat exchange pipe 100 is smaller than the reference data.

Further, it is determined that fouling is formed when the pressure drop amount calculated by the pressure gauge 421 installed at the inlet and outlet of the heat exchange pipe 100 is larger than the reference data.

In the present invention, a flow analysis (Computational Fluid Dynamics Analysis) is performed to obtain reference data for plasma spark generation.

In order to verify the accuracy of the flow analysis, the flow rate of the heat exchange pipe, the temperature and the pressure at the inlet and the outlet of the heat exchange pipe are measured under the steady state operating condition of the heat exchanger in which the fouling is not formed, . Then, these data are inputted to the control part and utilized as verification data of the flow analysis.

A pipe model having a degree of fouling to be a reference of plasma spark generation is modeled in the heat exchange pipe 100 under the same steady-state flow condition as that of the heat exchange pipe 100 installed in the tank 200, Fluid Dynamics Analysis) and calculate the pressure drop and temperature difference at the pipe inlet and outlet.

The pressure drop and temperature difference thus obtained are used as reference data for generation of plasma spark.

When the temperature difference calculated based on the temperature data obtained by the pair of thermometers 423 is smaller than the reference data for generating the plasma spark calculated through the flow analysis (Computational Fluid Dynamics Analysis), the controller 500 generates a plasma spark generation signal .

Further, when the pressure drop amount calculated based on the pressure data obtained by the pair of pressure gauges 421 is larger than the reference data for generating the plasma spark calculated through the flow analysis (Computational Fluid Dynamics Analysis), the controller 500 controls the plasma spark Generated signal.

In the present invention, the generation condition of the plasma spark is changed according to the degree of fouling formed in the heat exchange pipe (100).

Specifically, the control unit 500 increases the voltage of the plasma spark generation signal in proportion to the pressure drop amount or the temperature difference, thereby optimizing the generation condition of the plasma spark for fouling reduction.

In addition, the controller 500 adjusts not only the voltage of the plasma spark generation signal but also the duration of the plasma spark generation signal to design variables.

That is, the controller 500 increases the duration of the plasma spark generation signal in proportion to the pressure drop amount or the temperature difference.

The noise control of the fouling reduction system of the heat exchanger will be described.

Plasma sparks are generated in the electrode to reduce the formation of fouling in the heat exchange pipe. The resulting spark has a pipe for the heat exchanger and generates noise.

In the present invention, active noise control is applied in order to reduce the noise generated by the spark.

2 is a conceptual diagram illustrating the principle of active noise control. The graph of FIG. 2 (a) shows the vibration signal measured by the second sensor 430 mounted on the pipe for heat exchange, and the graph of FIG. 2 (b) (A), and (c) the graph shows that the vibration is canceled by superimposing the graph (a) and the graph (b).

The active noise control measures the noise of the control object, generates a noise signal of opposite phase to the noise signal, and superimposes both signals. As a result, it is possible to control the two noises to cancel each other to reduce the noise.

In the present invention, the vibration signal is measured instead of the noise of the heat exchanger as the control object. When noise is measured, not only the noise generated in the heat exchanger but also surrounding noise can be measured together, so that an appropriate noise reduction effect is not obtained as an active noise control signal reflecting unintended noise is generated .

Therefore, in the present invention, the second sensor 430 is mounted on the surface of the heat exchange pipe. At this time, the accelerometer 431 can be used as the second sensor 430.

Referring to FIG. 1, the second sensor 430 measures a vibration signal of the heat exchange pipe. The measured vibration signal is input to the control unit, and the control unit controls to generate the signal possessed by the vibrating means (600). A signal having a phase opposite to that of the measured vibration signal is generated for the active noise control.

The vibrating means 600 may use an actuator 610. [ The actuator 610 is excited according to the excitation signal transmitted by the controller 90. The actuator 610 can use a piezoelectric actuator with less electrical noise and precise control. The control unit is preferably implemented by a microcomputer.

Since the accelerometer 431 is spaced apart from the excitation means 600 by a certain distance, a time delay occurs when the vibration measured by the second sensor 430 reaches the excitation means 600 as long as the surrounding fluid is present. Therefore, for accurate active noise control, the control unit must generate a signal having the time delay.

The operation of the system for reducing the fouling of the heat exchanger will be described. First, the working fluid is introduced into the tank 200 through the inlet 210 of the tank 200. The working fluid introduced into the tank 200 is discharged to the outside of the tank 200 through the discharge port. At this time, the working fluid in the tank 200 is heat-transferred to the heated high temperature fluid inside the heat exchange pipe 100.

After a predetermined time, a fouling phenomenon occurs on the outer surface of the heat exchange pipe 100.

When the inlet / outlet pressure drop amount of the heat exchange pipe 100 is smaller than the reference pressure drop amount, the control unit 500 continuously monitors the flow rate of the heat exchange pipe 100, the temperature difference between the inlet and the outlet, and the pressure drop amount.

However, when the inlet / outlet pressure drop amount of the heat exchange pipe 100 is larger than the reference pressure drop amount or the inlet / outlet temperature difference of the heat exchange pipe 100 is smaller than the reference temperature difference, the controller 500 generates a plasma spark generation signal, Causing the part 300 to generate a plasma spark.

A plasma spark is generated on the outer surface of the heat exchange pipe 100 in the plasma generating part 300 to reduce fouling. That is, the power supply 320 of the plasma generating unit 300 supplies power to the electrode 310 to make the electrode 310 a positive electrode, and the electrode 310 connected to the grounding unit 330, The heat exchange pipe 100 becomes a (-) electrode. A plasma spark is generated between the electrode 310 and the outer surface of the heat exchange pipe 100 by the current supplied from the power supply 320, thereby reducing the fouling on the outer surface of the heat exchanger.

The fouling reduction system of the heat exchanger according to an embodiment of the present invention is configured such that the electrode 310 of the plasma generating part 300 is disposed adjacent to the outer surface of the heat exchange pipe 100 in the tank 200 A plasma spark is generated between the outer surface of the heat exchange pipe 100 and the electrode 310. When the high temperature fluid in the heat exchange pipe 100 and the working fluid in the tank 200 exchange heat, The occurrence of the ring can be reduced.

Further, in order to reduce the noise of the heat exchange device, the control unit first measures the vibration of the heat exchange pipe with the second sensor 430. The control unit generates an excitation signal having an opposite phase to the measured oscillation signal. In this case, the signal having the opposite phase is a signal in which the time delay is not reflected. Accordingly, the control unit generates the excitation signal reflecting the time delay required for the vibration measured by the second sensor 430 to reach the exciting means 600 once the surrounding fluid is present. Thereafter, the actuator 610 performs active noise control by causing the actuator 610 to oscillate according to the excitation signal reflecting the time delay.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Heat exchange pipe 100
Tank 200
Inlet 210
Outlet 230
The plasma generator 300
The electrode 310
Power Supply 320
Ground portion 330
Spark gap 340
Capacitor 350
Flow Meter 410
The first sensor 420
Pressure gauge 421
Thermometer 423
The second sensor 430
Accelerometer 431
The control unit 500
The means 600
Actuator 610

Claims (14)

A tank having an inlet through which the working fluid flows and an outlet through which the working fluid flows;
A heat exchange pipe disposed in the tank and performing heat transfer with the working fluid;
A plasma generator for generating a plasma spark in the heat exchange pipe;
A flow meter installed at an inlet of the heat exchange pipe to measure a flow rate;
A first sensor for measuring a physical quantity of an inlet and an outlet of the heat exchange pipe;
A second sensor for measuring vibration of the heat exchange pipe;
And a controller for determining whether or not the fouling occurs by comparing the data of the inlet and the outlet of the pipe for heat exchange measured from the first sensor with the reference data for generating plasma sparks through computational fluid dynamics analysis, A control unit for generating active signals and outputting a signal having a vibration signal measured by the second sensor as an input, thereby performing active noise control; And
And an excitation means for exciting the excitation signal according to the excitation signal. The method according to claim 1,
Wherein the vibration sensor is an accelerometer. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
Wherein the exciting means is an actuator. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
Wherein the excitation signal is an excitation signal having an opposite phase to the vibration signal measured by the second sensor. 5. The method of claim 4,
Wherein the excitation signal is applied with a time delay until a signal measured by the second sensor reaches the excitation means. ≪ Desc / Clms Page number 19 > The method according to claim 1,
Wherein the first sensors are formed as a pair and are pressure gauges measuring pressure at an inlet and an outlet of the heat exchange pipe. The method according to claim 1,
Wherein the first sensor is a pair of thermometers for measuring the temperature of the inlet and the outlet of the heat exchange pipe. The method according to claim 6,
The control unit generates a plasma spark generation signal when the pressure drop amount calculated based on the pressure data obtained by the pair of pressure gauges is larger than reference data for plasma spark generation calculated through a flow analysis (Computational Fluid Dynamics Analysis) Wherein the active noise control is applied to the fouling reduction system of the heat exchanger. 8. The method of claim 7,
The control unit generates a plasma spark generation signal when the temperature difference calculated based on the temperature data obtained by the pair of thermometers is smaller than the reference data for plasma spark generation calculated through a flow analysis (Computational Fluid Dynamics Analysis) A Fouling Reduction System for Heat Exchanger with Active Noise Control. The method according to claim 1,
The plasma generator may include:
An electrode for generating a plasma spark;
A power supply connected to the electrode to supply current to the electrode;
A grounding portion connected to the heat exchange pipe;
A spark gap coupled between the power supply and the electrode; And
And a capacitor disposed between the spark gap and the power supply, wherein the active noise control is applied to the fouling reduction system of the heat exchanger. The method according to claim 1,
Wherein an active noise control having an instantaneous voltage of 25 to 35 kV is applied when a plasma spark is generated by the plasma generator. The method according to claim 1,
Wherein the distance between the heat exchange pipe and the electrode is 1 to 10 mm. ≪ RTI ID = 0.0 > 11. < / RTI > 10. The method according to claim 8 or 9,
Wherein the control unit increases the voltage of the plasma spark generation signal in proportion to the pressure drop amount or the temperature difference. 10. The method according to claim 8 or 9,
Wherein the control unit increases the duration of the plasma spark generation signal in proportion to the pressure drop amount or the temperature difference.

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