KR102569864B1 - Earthquake-proof valve chamber and control method for the same - Google Patents

Abstract

The present invention relates to a valve chamber capable of safe operation in an earthquake situation and a method for controlling the same. a first seismic accelerometer 20 provided inside the main body 10 to sense vibrations inside the main body; a second seismic accelerometer 30 provided on the outside of the main body 10 to sense vibration of the ground outside the main body 10; A main valve (40) for opening and closing the pipe (P) penetrating the main body (10); A first pressure sensor 50 installed in the pipe (P) on the side of the fluid inflow based on the main valve 40 to measure the pressure of the fluid flowing in; From the second pressure sensor 60 and the first and second seismic accelerometers 30 installed in the pipe P on the side where the fluid flows out based on the main valve 40 to measure the pressure of the fluid flowing out. It is characterized in that it is composed of a control unit that receives vibration data from the first and second pressure sensors 60 and opens and closes the main valve 40 .

Description

Seismic valve chamber and its control method {EARTHQUAKE-PROOF VALVE CHAMBER AND CONTROL METHOD FOR THE SAME}

The present invention relates to a valve chamber, and more particularly, to a valve chamber capable of safe operation in an earthquake situation and a control method thereof.

In general, underground pipelines used for the movement of various fluids need to have valves installed in the middle for confluence, divergence, or other management purposes. The valve chamber is a space formed underground so that the valve of the underground pipeline can be installed, and is buried underground in the form of an empty box.

Korea has not taken special measures against earthquakes in the past because it is outside the seismic zone. Since large earthquakes are being observed, preparations for earthquakes are required. As for buildings, with the revision of the Building Act on September 16, 2011, the heads of local governments are required to check whether earthquake-resistant performance is secured, and preparations for earthquakes are being made to some extent. Vulnerability is a reality.

In general, it is known that the closer the underground structure is to the surface, that is, the shallower the depth, the greater the earthquake damage. There is also a research result that there is a possibility that it is necessary to prepare for earthquakes of underground structures regardless of the depth.

Until now, the approach to earthquake resistance of underground structures has been mainly implemented by a method of placing a gap between parts of a structure, placing a member capable of absorbing vibration such as an elastic body, or forming a reinforcing body.

'Patent Document 1' discloses an earthquake-resistant structure of a buried pipe as an example of an earthquake-resistant structure using air gaps. As shown in FIG. A gap (3) is formed between the inner tubes (2) and an annular sealing member (4) is interposed in the gap (3) so that the inner tube (2) swings between the gaps (3) even when there is vibration caused by an earthquake, so that the buried pipe It prevents breakage. In addition, 'Patent Document 2' discloses an earthquake-resistant structure of a manhole using a joint. As shown in FIG. 3, the manhole wall 6 outside the sewer main pipe 5 is removed with a cutting bit, and An earthquake-resistant joint 8 is inserted to allow the sewer main pipe 5 to flow, and the joint serves as a kind of elastic body.

In addition, 'Non-Patent Document 2' suggests a method of improving seismic performance using a fiber-reinforced composite.

However, this conventional approach has a problem in that it cannot properly maintain the role of the underground structure in response to an earthquake, although it may be able to prevent the destruction of the underground structure itself.

In particular, in the case of the valve chamber, which is the subject of this invention, it performs the function of controlling the flow of fluid flowing in underground water pipes, sewage pipes, gas pipes, oil pipelines, etc., and if the gas pipe or oil pipe is not blocked in the event of an earthquake, a large-scale explosion accident may occur, so it is necessary to block gas or oil, but there is a problem that such an accident cannot be prevented with the conventional approach.

In order to solve the above problem, 'Patent Document 3' proposes a technical idea of valve control according to earthquake detection, and the valve is unconditionally blocked when an earthquake of a certain magnitude or higher is detected, so that water or fuel necessary for earthquake response is supplied. As a result, there is a problem in that disaster response is delayed and unnecessary blocking occurs.

JP 2007-23522 A (2007. 2. 1.) JP 2011-241614 A (2011. 12. 1.) KR 10-2016-0038128 (2016. 4. 7.)

Shrestha Rajyaswori1 et al., The Effect of Overburden Depth on the Damage of Underground Structure during Earthquake, The 6th International Conference on Environmental Science and Civil Engineering, IOP Conf Series: Earth and Environmental Science, 2020. Jun-ho Jang and 3 others, An Analytical Study on the Applicability of Fiber Reinforced Composites for Improving the Seismic Performance of Columns, Journal of the Korea Society of Structure Diagnosis and Maintenance Engineering, Korea Society of Structure Diagnosis and Maintenance Engineering, 2012. 5., Vol. 16, No. 3, pp.117-127

The present invention has been made to solve the above problems, and the problem to be solved by the present invention is to provide a valve chamber capable of controlling a valve by determining whether a water pipe or the like should be blocked even in the event of an earthquake and a control method thereof will be.

An earthquake-resistant valve chamber according to the present invention includes a main body forming an outer periphery of the earthquake-resistant valve chamber; a first seismic accelerometer provided inside the main body to sense vibration inside the main body; a second seismic accelerometer provided on the outside of the main body to sense vibration of the ground outside the main body; a main valve opening and closing the tube passing through the main body; a first pressure sensor installed in a pipe on the side where the fluid flows in based on the main valve to measure the pressure of the fluid flowing in; Vibration data from the second pressure sensor and the first and second seismic accelerometers installed in the pipe on the side where the fluid flows out based on the main valve and measuring the pressure of the fluid flowing out, the first and second pressure sensors It is characterized in that it is composed of a control unit that receives pressure data from and opens and closes the main valve.

A method for controlling a seismic valve chamber according to the present invention includes a vibration sensing step of sensing vibration with a first seismic accelerometer installed inside the valve chamber and a second seismic accelerometer installed outside the valve chamber; A step performed when the seismic intensity detected by the first seismic accelerometer and the second seismic accelerometer is greater than or equal to a first reference seismic intensity in the vibration sensing step, wherein the amplitude and frequency of the vibration detected by the first seismic accelerometer and the second seismic accelerometer are a vibration matching determination step of determining whether an earthquake has occurred based on whether the earthquake is coincident or within a predetermined range; a seismic intensity determining step of determining whether or not one or more of the seismic intensities detected by the first seismic accelerometer or the second seismic accelerometer is greater than or equal to a second reference seismic intensity and determining a higher seismic intensity as the measured seismic intensity; A valve control step of blocking the flow of fluid by closing a main valve installed in a pipe passing through a valve chamber when the measured progress is greater than or equal to a second reference progress; the valve control step determining whether seismic intensities measured by the first seismic accelerometer and the second seismic accelerometer are both less than a first reference seismic intensity; A pressure measurement step of measuring the pressures of the first pressure sensor and the second pressure sensor installed in the pipe before and after the main valve, and comparing the pressure difference between the first pressure sensor and the second pressure sensor with the pressure difference before and after closing the main valve. It is technically characterized in that it consists of a pressure matching determination step of determining whether the main valve is opened or not.

According to the seismic valve chamber and control method according to the present invention, the flow of fluid can be controlled by considering the pressure of the pipe penetrating the valve chamber in addition to seismic intensity.

In addition, when the vibration is relieved, it is possible to return to the normal state after the earthquake by flowing the fluid through the pipe according to the pressure.

1 is a case diagram of earthquake damage according to depth
2 is an earthquake-resistant structure using air gaps
Figure 3 is an earthquake-resistant structure using a joint
4 to 6 are configuration diagrams of an earthquake-resistant valve chamber according to the present invention
7 is a flow chart of a method for controlling an earthquake-resistant valve chamber according to the present invention;
8 is a detailed flow chart of a pressure match determination step
9 is a processing flow chart when the progress is equal to or greater than the first reference progress and less than the second reference progress;
10 is another embodiment of an earthquake-resistant valve chamber according to the present invention

Hereinafter, a seismic valve chamber and a control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

4 to 6 are perspective views of the valve chamber according to the present invention viewed from the front, side, and plane directions, respectively, as configuration diagrams of the earthquake-resistant valve chamber according to the present invention. The seismic valve chamber according to the present invention includes a main body 10, a first seismic accelerometer 20, a second seismic accelerometer 30, a main valve 40, a first pressure sensor 50, a second pressure sensor 60, and It is composed of a control unit (not shown).

The main body 10 is a component forming the outer periphery of the earthquake-resistant valve chamber according to the present invention, and is formed in the form of a box buried in the ground and having an empty inside.

The first seismic accelerometer 20 is provided inside the main body 10 and is a component that detects vibration inside the main body 10, and the second seismic accelerometer 30 is provided outside the main body 10 to detect vibration inside the main body 10 ( 10) It is a component that senses the vibration of the external ground. The reason why the two seismic accelerometers 20 and 30 are installed inside and outside the main body 10 in the present invention is that the pipe P through which the fluid flows penetrates the main body 10 in the earthquake-resistant valve chamber according to the present invention. This is because if a non-ideal flow occurs, it can be mistaken for vibration caused by an earthquake. That is, such misrecognition can be eliminated by placing the second seismic accelerometer 30, which is not subject to vibrations caused by the fluid.

The main valve 40 is a component that is installed in a pipe P penetrating the main body 10, such as a water pipe or a gas pipe, to control the flow of fluid by opening and closing the pipe P.

The first pressure sensor 50 is a component installed in the pipe P on the side where the fluid flows in based on the main valve 40 and measures the pressure of the incoming fluid, and the second pressure sensor 60 is the main It is a component that is installed in the pipe (P) on the side of the fluid outflow based on the valve 40 and measures the pressure of the fluid outflow. In the present invention, the inlet and outlet pressures are compared to determine whether or not the pipe P should be blocked, which will be described in detail in the control method.

The control unit receives vibration data from the first and second seismic accelerometers 30 and pressure data from the first and second pressure sensors 60 and operates the main valve 40 according to the method for controlling an earthquake-resistant valve chamber according to the present invention. It is a component that opens and closes.

The earthquake-resistant valve chamber according to the present invention configured as above can control the flow of the fluid flowing through the pipe P based on the vibration data and the pressure data. Hereinafter, a method for controlling an earthquake-resistant valve chamber according to the present invention will be described.

7 is a flow chart of a control method of an earthquake-resistant valve chamber according to the present invention. The control method of an earthquake-resistant valve chamber according to the present invention includes a vibration detection step (S10), a vibration matching determination step (S20), a progress determination step (S30), It consists of a valve control step (S40), a progress rediscovery step (S50), a pressure measurement step (S60), and a pressure match determination step (S70).

In the vibration detection step (S10), vibration is continuously sensed by the first seismic accelerometer 20 and the second seismic accelerometer 30, and continuous detection is maintained because it is unknown when an earthquake will occur. In the vibration detection step (S10), when the amplitude of vibration equal to or higher than the first reference seismic intensity is detected by both the first seismic accelerometer 20 and the second seismic accelerometer 30, it is considered that there is a possibility of an earthquake and the vibration matching determination step (S20) transition to In addition, when an amplitude of vibration equal to or higher than the first reference seismic intensity is detected by any one or more of the first seismic accelerometer 20 or the second seismic accelerometer 30, an alarm indicating that the vibration has been detected is issued to a control room, etc. can make comparisons possible. For reference, according to the experiment conducted by the inventors of the present invention, a first standard magnitude of 4.0 is appropriate.

The vibration matching determination step (S20) is a step of determining whether an actual earthquake has occurred from the vibrations detected by the first earthquake accelerometer 20 and the second earthquake accelerometer 20 and the second earthquake accelerometer 20 and the second earthquake. It may be determined whether the amplitude and frequency of the vibration measured by the accelerometer 30 match or are within a predetermined range. For example, the case where the amplitude of vibration measured by the first seismic accelerometer 20 compared to the amplitude of vibration measured by the second seismic accelerometer 30 is in a first predetermined range, for example, 80 to 120% is reported as matching It can be judged from the vibration caused by the same cause, that is, an earthquake. If it is out of the predetermined range, it is highly likely to be caused by a temporary shock or a fluid flowing through the pipe (P), so it is not judged as an earthquake.

A similar approach is possible in the case of frequency, but the frequency can be judged at the matching level by narrowing the predetermined range more than the amplitude. Because, in the case of the amplitude, the magnitude may vary depending on the state in which the seismic accelerometers 20 and 30 are coupled to the main body 10, for example, whether it is a rigid coupling or an elastic coupling, but the frequency is difficult to change. Because. The vibration frequency measured by the first seismic accelerometer 20 and the second seismic accelerometer 30 is similar to the case where an external force acts on a system with mass and attenuation since the vibration caused by an earthquake is applied to the seismic accelerometer. It is possible to determine whether there is an earthquake by coincidence, and the coincidence of the vibration frequencies is determined by Fourier transforming the vibration waveforms measured by the first seismic accelerometer 20 and the second seismic accelerometer 30 to determine whether the peak (maximum point) frequencies match. It can be known whether Even if the waveform of vibration caused by an earthquake is irregular, the waveform can be viewed as a primary combination of a plurality of sinusoidal waves (sin, cos waves), and since the frequency of each sinusoid can be known through Fourier transform, it is possible to determine whether it is an earthquake regardless of the vibration waveform. that can be judged. Several peak frequencies may be generated, and a comparison of only the top three in order of peak values is sufficient for determination. This is because although the Fourier transform values of the vibration waveforms measured by the first seismic accelerometer 20 and the second seismic accelerometer 30 may be different, the order of the peak frequencies is almost the same (for example, the first seismic accelerometer 20 ), if ω1, ω2, and ω3 have the largest peak values, the frequencies with the largest peak values in the second seismic accelerometer 30 are also the same).

When it is determined in the vibration matching determination step (S20) that the vibration is matched, that is, an earthquake has occurred, the process proceeds to the magnitude determination step (S30).

In the seismic intensity determination step (S30), it is determined whether or not one or more of the amplitude of the vibration sensed by the first seismic accelerometer 20 or the second seismic accelerometer 30, that is, the seismic intensity is greater than or equal to the second reference seismic intensity. This is to treat differently according to the severity of In the seismic intensity determination step (S30), a larger value among seismic intensities detected by the first seismic accelerometer 20 and the second seismic accelerometer 30 is determined as the measured seismic intensity. According to the experiments conducted by the inventors of the present invention, the second reference magnitude of 7.0 is appropriate.

The valve control step (S40) is performed when the magnitude of the earthquake is greater than the second reference magnitude in the magnitude determination step (S30). An alarm is issued to a situation room that monitors an earthquake-resistant valve chamber according to the present invention.

The seismic intensity re-detection step (S50) is performed to determine whether the main valve 40 should be continuously closed or opened after the valve control step (S40), and the first seismic accelerometer 20 and the second seismic accelerometer 30 ) When all of the measured progress are less than the first reference progress, the transition is made to the pressure measuring step (S60). If at least one of the seismic intensities measured by the first seismic accelerometer 20 and the second seismic accelerometer 30 is less than the first reference seismic intensity, the seismic intensity re-detection step (S50) is continuously performed with the main valve 40 closed. carry out

The pressure measuring step (S60) is a step of measuring the pressures of the first pressure sensor 50 and the second pressure sensor 60.

The pressure matching determination step (S70) is a step of comparing the pressure difference between the first pressure sensor 50 and the second pressure sensor 60 and the pressure difference before and after closing the main valve, depending on whether the pressure is matched, the main valve 40 decide whether to open

8 is a detailed flow chart of the pressure matching determination step, first, the pressure measured by the first pressure sensor 50 compared to the pressure measured by the second pressure sensor 60 is in a second predetermined range, for example, in the range of 80 to 120% In this case, it is determined that there is no problem with the pipes in the front and rear of the earthquake-proof valve chamber according to the present invention, and the main valve 40 can be opened. If the pressure ratio outside the second predetermined range is shown, there is no reason to open the main valve 40 in any case because the pipe is destroyed in the front or rear of the earthquake-resistant valve chamber according to the present invention.

Next, if the pressures measured by the first pressure sensor 50 and the second pressure sensor 60 are in the third predetermined range (80 to 120%) compared to the pressure measured before the vibration matching determination step (S20), the fluid in a normal state Since it can be seen that the amount is filled in the pipe (P), the main valve 40 is opened and an alarm is issued to the situation room. If it exceeds the third predetermined range, the main valve 40 should not be opened because abnormal pressure is acting due to some factor, and if it is below the predetermined range, the fluid amount is abnormally small and the fluid cannot move downstream. Therefore, there is no need to open the main valve 40.

In the seismic intensity determination step (S30), if the seismic intensity is equal to or greater than the first reference magnitude and less than the second reference magnitude, since the risk due to an earthquake is moderate, whether or not the main valve 40 is opened is determined by the pressure of the pipe (P).

9 is a processing flow chart when the progress is greater than or equal to the first reference progress and less than the second reference progress, and the pressure measurement step (S60) is performed to measure the pressures of the first pressure sensor 50 and the second pressure sensor 60 And, if the pressure measured by the first pressure sensor 50 and the second pressure sensor 60 is within a third predetermined range (80 to 120%) compared to the pressure measured before the vibration matching determination step (S20), it is determined as a normal situation. and keep the main valve 40 open.

If not, since the pressure is abnormal, the main valve 40 is closed once and an alarm is issued to the situation room. Subsequent processing is the same as after the progress rediscovery step (S50).

Although the seismic valve chamber and its control method according to the present invention have been described above, the first seismic accelerometer 20 can be flexibly installed with respect to the main body 10 in order to increase sensitivity to vibration.

10 is another embodiment of an earthquake-resistant valve chamber according to the present invention, in which an elastic body 70 is interposed between the main body 10 and the first seismic accelerometer 20, and vibration is applied to the first seismic accelerometer 20 The vibration is generated with a larger amplitude than when the first seismic accelerometer 20 is firmly attached to the body 10.

For example, as shown in FIG. 10 (a), when the elastic body 70 protrudes horizontally from the side wall of the body 10 and the first seismic accelerometer 20 is installed at the end, vibration in the vertical direction occurs with a large amplitude do. Therefore, detection sensitivity of the S wave in which vertical vibration is generated can be increased. However, in the case of seismic waves, the P wave, which is a longitudinal wave, arrives first, and since the P wave generates horizontal vibrations, it is advantageous to increase the detection sensitivity of the P wave in order to quickly detect an earthquake. To do so, the elastic body 70 may protrude vertically from the ceiling or floor of the main body, and the first seismic accelerometer 20 may be installed at the end thereof. Alternatively, considering both horizontal and vertical sensitivity, as shown in FIG. 10 (b), the elastic body 70 is inclined from the sidewall, ceiling, and floor of the main body 10 at an angle, for example, 45 ° (45 ° It is considered an appropriate value because it can equally improve the sensitivity in the vertical and horizontal directions) and the first seismic accelerometer 20 is installed at the end to improve the sensitivity to P waves and S waves at the same time.

In the case of the embodiment of FIG. 8 , since the sensitivity of the first seismic accelerometer 20 is high and the sensitivity of the second seismic accelerometer 30 remains the same, it is meaningless to compare amplitudes of vibration as they are when using the same seismic accelerometer. Instead, even if a low-sensitivity, low-priced product is used as the first seismic accelerometer 20, it can be used with the same sensitivity as the second seismic accelerometer 30, which has the advantage of reducing the manufacturing cost of the device. However, in this case, the elasticity of the elastic body 70 should be appropriately adjusted so that the sensitivities of the first seismic accelerometer 20 and the second seismic accelerometer 30 are the same. Before adjusting and comparing the vibration data measured by the second seismic accelerometer 30, the control unit pre-processes the vibration data measured by the first seismic accelerometer 20 to determine the first and second seismic accelerometers 30 by software. Sensitivity needs to be matched.

In addition, the earthquake-resistant valve chamber according to the present invention can respond even when the pipe (P) is damaged due to a cause other than an earthquake. For example, the pressure measured by the first pressure sensor 50 or the second pressure sensor 60 is less than the normal pressure set as a predetermined value (eg 10 kgf/cm 2 ) (eg 5 kgf/cm 2 ). ) If it falls into the earthquake-resistant valve chamber according to the present invention, it is considered that the pipe (P) is damaged and the main valve 40 can be closed. In addition, when the pressure measured by the first pressure sensor 50 or the second pressure sensor 60 recovers to a normal pressure or higher set as a predetermined value (10 kgf/cm 2 ), the main valve 40 may be opened again. .

10 main body 20 first seismic accelerometer
30 Second seismic accelerometer 40 Main valve
50 first pressure sensor 60 second pressure sensor
70 elastomer
S10 Vibration detection step S20 Vibration matching determination step
S30 progress judgment step S40 valve control step
S50 Progress rediscovery step S60 Pressure measurement step
S70 pressure matching judgment step

Claims (10)

A main body 10 forming an outer circumference of the earthquake-resistant valve chamber;
a first seismic accelerometer 20 provided inside the main body 10 to sense vibration inside the main body 10;
a second seismic accelerometer 30 provided on the outside of the main body 10 to sense vibration of the ground outside the main body 10;
A main valve (40) for opening and closing the pipe (P) penetrating the main body (10);
A first pressure sensor 50 installed in the pipe (P) on the side of the fluid inflow based on the main valve 40 to measure the pressure of the fluid flowing in;
A second pressure sensor 60 installed in the pipe P on the side where the fluid flows out based on the main valve 40 to measure the pressure of the fluid flowing out, and
Consisting of a controller that opens and closes the main valve 40 by receiving vibration data from the first and second seismic accelerometers 20 and 30 and pressure data from the first and second pressure sensors 50 and 60, ,
Between the main body 10 and the first seismic accelerometer 20, an elastic body 70 protruding in an oblique state from the sidewall, ceiling, or floor of the main body 10 is interposed,
An earthquake-proof valve chamber, characterized in that the first seismic accelerometer (20) is provided at the end of the elastic body (70).
The method of claim 1,
The earthquake-proof valve chamber, characterized in that the main valve (40) is closed when the pressure measured by the first pressure sensor (50) or the second pressure sensor (60) falls below the normal pressure set as a predetermined value.
The method of claim 2,
The main valve 40 opens again when the pressure measured by the first pressure sensor 50 or the second pressure sensor 60 from which the pressure below the normal pressure is measured recovers to the normal pressure or higher set as the predetermined value. A seismic valve chamber, characterized in that.
The method of claim 3,
An earthquake-proof valve chamber, characterized in that the angle formed by the elastic body 70 and the side wall, ceiling or floor of the main body 10 is 45 °.
delete A vibration sensing step (S10) of sensing vibration with a first seismic accelerometer 20 installed inside the valve chamber and a second seismic accelerometer 30 installed outside the valve chamber;
A step performed when the seismic intensities detected by the first seismic accelerometer 20 and the second seismic accelerometer 30 in the vibration sensing step (S10) are equal to or greater than a first reference seismic intensity, wherein the first seismic accelerometer 20 and the 2 a vibration matching determination step (S20) of determining whether an earthquake has occurred based on whether the amplitude and frequency of the vibration detected by the seismic accelerometer 30 match or are within a predetermined range;
A seismic intensity determination step (S30) of determining whether or not one or more of the seismic intensities detected by the first seismic accelerometer 20 or the second seismic accelerometer 30 is equal to or greater than a second reference seismic intensity and determining a higher seismic intensity as the measured seismic intensity (S30) ;
A valve control step (S40) of blocking the flow of fluid by closing the main valve 40 installed in the pipe (P) passing through the valve chamber when the measured progress is equal to or greater than the second reference progress;
The valve control step (S40);
A pressure measuring step (S60) of measuring the pressures of the first pressure sensor 50 and the second pressure sensor 60 installed in the pipe P before and after the main valve 40, and
In the pressure matching determination step (S70) of determining whether the main valve 40 is open by comparing the pressure difference between the first pressure sensor 50 and the second pressure sensor 60 and the pressure difference before and after closing the main valve. A control method of an earthquake-resistant valve chamber, characterized in that configured.
The method of claim 6,
In the vibration matching determination step (S20), when the amplitude of the vibration measured by the first seismic accelerometer 20 compared to the amplitude of the vibration measured by the second seismic accelerometer 30 is within a first predetermined range, it is reported as matched. A control method of an earthquake-resistant valve chamber, characterized in that it is determined by vibration caused by an earthquake.
The method of claim 7,
In the pressure match determination step (S70), the pressure measured by the first pressure sensor 50 compared to the pressure measured by the second pressure sensor 60 is in a second predetermined range, and the first pressure sensor 50 And when the pressure measured by the second pressure sensor 60 is within a third predetermined range compared to the pressure measured before the vibration match determination step (S20), the main valve 40 is opened and an alarm is transmitted to the situation room. Control method of the seismic valve chamber to be.
The method of claim 6,
The control method of the earthquake-proof valve chamber, characterized in that the first reference seismic intensity is 4.0, and the second reference seismic intensity is 5.0.
The method of claim 8,
The method of controlling an earthquake-resistant valve chamber, characterized in that the first predetermined range, the second predetermined range, and the third predetermined range are all 80 to 120%.