JP2004240840A - Pressure regulator control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure regulator control system which performs adjustment so as to maintain correct response to the environment where load or the like is constantly changing. <P>SOLUTION: When the load is small, only a governor 1 is operated. A governor 2 starts to operate when a detecting means 40 detects that a valve-opening reaches 80% which is set as an upper limit of normal operation state. Secondary pressure P2 of the governor 2 is detected by a pressure gauge 62, and degree of deviation of variation from a predefined range is determined by a deviation determination means 63. Speed of response of a servo amplifier 61 is set to a little higher, and a speed modification means 64 reduces it by degrees according to the degree of the deviation. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention adjusts the control state of a pressure regulator provided in a pipeline system for transporting a fluid to reduce a primary pressure to a secondary pressure and suppress a pressure fluctuation due to a flow rate fluctuation so as to obtain an appropriate responsiveness. The present invention relates to a pressure regulator control system.
[0002]
[Prior art]
Conventionally, in a pipeline system that transports fluid such as a city gas supply system, in order to supply fluid at a constant pressure to a load, the supplied primary pressure is reduced, and even if the flow rate changes, the secondary pressure is reduced. A pressure regulator for controlling the pressure fluctuation is provided. A pressure regulator is also called a governor.
[0003]
For example, in the case of city gas supplied to a residential area, the load increases during a time when cooking, bathing, and the like are frequently performed, but the load does not increase so much during other times. If the load is usually smaller than the peak load, a plurality of governors are often connected in parallel. In a multi-system governor system in which a plurality of governors are connected in parallel, an emergency shutoff valve is connected in series for each governor (for example, see Patent Document 1).
[0004]
4A shows a simplified configuration of a two-sequence governor system representing a multi-sequence governor system, and FIG. 4B shows its operation characteristics. Fluid such as city gas supplied from the primary conduit 10 is regulated in pressure by the two governors 11 and 12 and supplied to the load of the secondary conduit 20. Emergency shutoff valves 21 and 22 are connected to the governors 11 and 12, respectively. Fluid is supplied to the governors 11 and 12 from the primary line 10 at the primary pressure P1 via the emergency shutoff valves 21 and 22. The two-system governor system 30 includes a first system 31 including the governor 11 and the emergency shutoff valve 21, and a second system 32 including the governor 12 and the emergency shutoff valve 22. Each governor 11, 12 reduces the primary pressure P1 to near the secondary pressure P2. That is, P1> P2.
[0005]
If a failure or the like occurs in any of the governors 11 and 12 and the pressure reducing function is impaired, there is a possibility that a high primary pressure P1 may be applied to the secondary pipeline 20, so the emergency shutoff valves 21 and 22 are provided, respectively. Although not shown, the shutoff operation is performed by detecting an abnormal operation such as the secondary pressure of the governor 11 or 12. By shutting off the emergency shutoff valve on the system side including the governor in which the malfunction has occurred, the pressure increase in the secondary pipeline 20 is prevented. Usually, the emergency cutoff valves 21 and 22 are in a fully open state.
[0006]
The detection unit 40 detects, for example, a valve opening degree as an operation state of the governor 11 of the first series 31. The governor 12 of the second series 32 operates so that the valve opening of the governor 11 of the first series detected by the detection means 40 stays near the value set as the upper limit of the normal operation state.
[0007]
FIG. 4B shows the relationship between the flow rates of the governors 11 and 12 and the pressure on the secondary side. The flow rate of the fluid substantially corresponds to the valve opening. Each governor 11, 12 has an operation characteristic as shown as L11, L12, respectively. When the load is small, the operating characteristic L12 of the governor 12 of the second series 32 is set such that the governor 11 of the first series 31 operates and the governor 12 of the second series 32 waits. 11 is set to operate on a lower pressure side than the operation characteristic L11. However, the governor 11 of the second series 32 starts operating so that the governor 11 of the first series 31 sets the valve opening degree, for example, 80% as the upper limit of the normal operation state, and the governor 11 stays near the upper limit. . The set pressure of the governor 12 is adjusted so as to increase, and as a result, an operation characteristic as indicated by L20 is obtained.
[0008]
When the valve opening of the governor 11 of the first system 31 is larger than 80% of the upper limit, the set pressure of the governor 12 of the second system 32 is adjusted to increase, and the valve opening of the governor 12 increases, Fluid is also supplied to the load via governor 12. As a result, the valve opening degree of the governor 11 of the first series 31 is reduced, and it is possible to prevent the governor 11 from greatly exceeding the upper limit. When the valve opening of the governor 11 of the first series 31 becomes smaller than the upper limit due to the decrease of the load or the operation of the governor 12 of the second series 32, the set pressure of the governor 12 of the second series 32 decreases, and the valve opening becomes descend. If the load is within the upper limit of 80% of the valve opening of the governor 11 of the first system 31, the governor 12 of the second system 32 will be in the fully closed state with the valve opening being 0. That is, when the flow rate is small, only the governor 11 of the first system operates to perform the pressure regulation.
[0009]
[Patent Document 1]
JP-A-11-282543
[Problems to be solved by the invention]
In the two-system governor system 30 as shown in FIG. 4A, one governor 11 is used from a small flow area to a large flow area, and the other governor 12 is used in a large flow area. The governor 12 of the second series 32 is feedback-controlled so as to maintain the upper limit of the valve opening of the governor 11 of the first series 31 of 80%. Such feedback control involves an excessive response when the load changes.
[0011]
That is, the governor 12 of the second series 32 is controlled while adjusting its own set pressure so that the opening degree of the governor 11 of the first series 31 is maintained at a specified value. Done in If an output capable of responding to a feedback signal (input) such as an opening degree at a high speed is generated by the detection means 40 functioning as a controller, it is expected that agile and highly accurate control can be performed. . However, if the reaction is too fast, hunting due to over-response occurs. When hunting occurs, the control is not stabilized, and the fluctuation of the secondary pressure continues. Further, a governor valve or the like may be worn due to sliding of a mechanical part or may be fatigued due to repeated deformation, thereby shortening the service life. For these reasons, it is difficult to always maintain proper responsiveness in an environment where the load and the like change every moment.
[0012]
An object of the present invention is to provide a pressure regulator control system that can be adjusted to maintain appropriate responsiveness in an environment where a load or the like changes every moment.
[0013]
[Means for Solving the Problems]
The present invention provides a pressure regulator that controls the fluid supplied from the primary side to the secondary side under reduced pressure and controls the fluid pressure to maintain a predetermined secondary pressure with respect to the fluctuating supply flow rate. A pressure regulator control system that adjusts to
Indicator detecting means for detecting an indicator reflecting the control operation of the pressure regulator,
Departure determining means for determining the extent to which the index detected by the index detecting means deviates from a preset range within a period set in advance to a fluctuation cycle of the supply flow rate of the fluid,
Speed change means for partially changing the response speed of control of the pressure regulator according to the degree of deviation determined by the deviation determination means in a direction in which the degree of deviation approaches a predetermined reference degree. A pressure regulator control system characterized by the following.
[0014]
According to the present invention, a pressure regulator control system supplies a fluid supplied from the primary side to the secondary side while reducing the pressure, and controls the pressure regulator to maintain a predetermined secondary pressure with respect to the varying supply flow rate. In order to obtain a proper response, an index detecting unit, a deviation determining unit, and a speed changing unit are included. Since the index detecting means detects an index on which the control operation of the pressure regulator is reflected, the state of the control operation of the pressure regulator can be grasped based on the detected index. The deviation determining means determines the degree of deviation of the index detected by the index detecting means from the preset range within a period set in advance in a fluctuation cycle of the supply flow rate of the fluid. The degree of deviation of the index from the set range can be determined so as not to be affected by the dynamic fluctuation. The speed changing unit partially changes the response speed of the control of the pressure regulator according to the degree of deviation determined by the deviation determining unit in a direction in which the degree of deviation approaches a predetermined reference level. The response speed can be gradually improved to an appropriate state.
[0015]
Also, in the present invention, a plurality of the pressure regulators operate simultaneously and in parallel,
At least one pressure regulator performs a control operation of the secondary pressure such that an operation state of another pressure regulator is within a predetermined range.
[0016]
According to the present invention, if the response speed of the pressure regulator is made too fast, hunting occurs, and the result affects other pressure regulators, and the operating state of the pressure regulator also fluctuates. This fluctuation further causes a change in the response speed. Even when the load is stabilized, one of the two regulators has a large opening and the other has a small opening. There is a risk that the situation will be repeated with a large state. In such a situation, the index easily deviates from the set range, so that the response speed can be adjusted so as to reduce the deviation of the index, and an appropriate control state can be obtained.
[0017]
Further, in the present invention, the index detecting means detects at least one of the opening degree and the pressure of the pressure regulator as the index.
[0018]
According to the present invention, at least the opening or the pressure is detected as an index reflecting the control operation of the pressure regulator. In a control in which the pressure regulator keeps the secondary pressure constant even when the supply flow rate of the fluid fluctuates, the opening degree of the valve changes, and the opening degree of the valve changes depending on the pressure such as the secondary pressure and the pilot pressure. Since the opening is a mechanical displacement, it can be easily grasped. The pressure can be easily detected from a pipe or the like.
[0019]
In the present invention, the response speed of control of the pressure regulator is set to be faster than an expected appropriate response speed.
[0020]
According to the present invention, since the response speed of the pressure regulator control is set faster than the expected appropriate response speed, the degree of the index deviating from the predetermined range becomes large at the beginning of adjustment, and the fast response speed is increased. Can be gradually reduced so that an appropriate response speed can be obtained. If the adjustment is started from a state where the response speed is low, even if hunting occurs and the index deviates, there is a possibility that the response speed is erroneously determined to be a state where the response speed is high and the state is further adjusted to a state where the response speed is too slow. .
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a two-system governor system according to an embodiment of the present invention. In the present embodiment, similarly to FIG. 4, the operation state of the second system governor 2 is controlled so that the opening degree of the first system governor 1 of the two system governor system is maintained at a specified value. The governors 1 and 2 control the valves 3 and 4 to open and close, respectively, to reduce the pressure of the gas supplied from the primary line 10 to the secondary line 20 to maintain a constant secondary pressure. In the valves 3 and 4, the gap between the valve bodies 3a and 4a and the valve seats 3b and 4b corresponds to the opening. The valve bodies 3a and 4a are mounted on lower ends of the valve rods 3c and 4c, respectively, and the valve seats 3b and 4b are fixed to casings of the governors 1 and 2, respectively. The valve stems 3c, 4c are connected to the diaphragms 3d, 4d and the springs 3e, 4e, respectively, at an intermediate portion. The diaphragms 3d and 4d and the springs 3e and 4e are housed in the diaphragm chambers 3f and 4f, respectively. The diaphragms 3d, 4d partition the inside of the diaphragm chambers 3f, 4f into two parts. In the lower space partitioned by the diaphragms 3d, 4d in the diaphragm chambers 3f, 4f, an intermediate space between the pilot valves 5, 6 connected between the primary pipeline 10 and the secondary pipeline 20 and the throttles 7, 8 is provided. Pressure is introduced. In the upper space partitioned by the diaphragms 3d, 4d in the diaphragm chambers 3f, 4f, a secondary pressure from the secondary pipeline 20 is introduced, and the springs 3e, 4e are stored, respectively. Such governors 1 and 2 can control the secondary pressure by the set pressure of the pilot valves 5 and 6.
[0022]
In the two-system governor system according to the present embodiment, the valve opening of the first system governor 1 is detected by the detection means 40, and the second system governor 1 is controlled so that the valve opening does not exceed 80% as in FIG. The governor 2 operates. The control of the governor 2 of the second system is performed by mechanically driving the set pressure of the pilot valve 6 from the motor 50 via the transmission mechanism 51. The controller 60 is used to electrically drive the motor 50 based on the valve opening of the governor 1 detected by the detection means 40. The controller 60 includes a servo amplifier 61. The servo amplifier 61 drives the motor 50 to rotate based on the opening detection output of the detection means 40.
[0023]
The servo amplifier 61 of the present embodiment can control the gain and finely adjust the response speed in multiple steps. The response speed is adjusted by detecting the secondary pressure P2 as an index corresponding to the operating state of the governor 2 with the pressure gauge 62, and determining the degree of the deviation from a preset range by a deviation determining means 63 in the controller 60. Determined by When the deviation determining unit 63 determines that the degree of deviation is large, the speed changing unit 64 in the controller 60 changes the response speed of the servo amplifier 61.
[0024]
FIG. 2 shows the basic concept of changing the response speed of the servo amplifier 61 according to the present embodiment. The control procedure of the change is started from step s0, and the response speed of the servo amplifier 61 is set to be higher than the speed expected to be appropriate. In step s1, it is determined whether the secondary pressure P2 has reciprocated the threshold value n times or more within a predetermined period. n is set according to the length of the period. For example, the setting is made on the assumption that several times per minute are allowed. In step s1, when the fluctuation of the secondary pressure P2 within the predetermined period is small and the number of times of reciprocating the threshold is smaller than n, the process returns to step s1 to continue monitoring the secondary pressure P2. In step s1, when the fluctuation of the secondary pressure P2 within the predetermined period is large and the number of times of reciprocating the threshold value becomes n or more, the response speed of the servo amplifier 61 is reduced in step s2, and the control speed of the motor 50 is reduced. Is lowered by one rank.
[0025]
Since the response speed of the servo amplifier 61 is set to be faster than the appropriate response speed expected for the governor 2, the secondary pressure P2 greatly deviates from a predetermined range at the beginning of the adjustment. Can be gradually reduced so that an appropriate response speed can be obtained. If adjustment is started from a state where the response speed is slow, even if hunting occurs and the secondary pressure P2 deviates, it is erroneously determined that the response speed is fast, and the response speed is further decreased, and the response speed is too slow. There is a possibility that it will be in a state.
[0026]
FIG. 3 shows an example of setting a pressure range when adjusting the control state of the governor 2 using the secondary pressure P2 as an index. Assuming that the target pressure as the secondary pressure P2 is ps, an upper limit pmax and a lower limit pmin are considered as allowable ranges of the secondary pressure P2. If the upper threshold value pu is set between the target pressure ps and the upper limit pmax, and the response speed of the servo amplifier 61 is slightly reduced, the fluctuation of the secondary pressure P2 is large, and the frequency of exceeding the at least the upper threshold value pu is increased. . If the response speed of the servo amplifier 61 is decreased, the fluctuation of the secondary pressure pu becomes small, and the secondary pressure pu falls within an appropriate range.
[0027]
Since the fluctuation of the secondary pressure P2 also occurs according to the fluctuation of the flow rate supplied to the load, in the case of city gas, etc., the upper threshold value pu is considered in consideration of the influence of the flow rate change due to the time of day, the seasonal flow rate change and the like. Is allowed to exceed a certain number of times. The upper threshold value pu can be changed depending on the season, and the criterion for the number of times can be changed depending on the season. In addition, not only the upper side of the secondary pressure P2, but also a lower threshold value pl is set to determine whether the secondary pressure P2 deviates from a range between the upper threshold value pu and the lower threshold value pl. You can also.
[0028]
Although the secondary pressure P2 is used as an index reflecting the operation state of the governor 2, a pilot pressure or the like can be used as an index similarly. Further, the opening degree of the valve 4 can also be used as an index. Further, the concept of the present invention can be similarly applied to a governor that operates independently or a governor of a multi-system governor system that operates with three or more systems, and can set an appropriate response speed. Further, the governor format can be similarly applied to those other than those shown in FIG.
[0029]
【The invention's effect】
As described above, according to the present invention, the index reflecting the control operation of the pressure regulator is detected, and the degree of the index deviating from the preset range is affected by the instantaneous fluctuation of the supply flow rate of the fluid. It can be determined that there is not. Since the response speed of control of the pressure regulator is partially changed in a direction in which the degree of deviation of the index approaches a predetermined reference level, the response speed can be gradually improved to an appropriate state.
[0030]
Further, according to the present invention, between the two pressure regulators, a state in which one opening is large and the other is small, and a state in which one opening is small and the other is large are repeated. Can be prevented and an appropriate control state can be obtained.
[0031]
Further, according to the present invention, it is possible to use an easily detected opening degree and pressure as an index reflecting the control operation of the pressure regulator.
[0032]
According to the present invention, the response speed of the pressure regulator control is set to be faster than an expected appropriate response speed, and even if the index deviates from a predetermined range in the initial stage of the adjustment, the response speed is increased. Can be gradually reduced so that an appropriate response speed can be obtained.
[Brief description of the drawings]
FIG. 1 is a simplified block diagram showing a configuration of a two-system governor system according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a basic concept of adjusting a control speed of a motor in the two-system governor system of FIG. 1;
FIG. 3 is a graph showing a concept of determining whether or not the deviation of the secondary pressure P2 has deviated from the deviation determining means of FIG. 1;
FIG. 4 is a piping diagram showing a simplified configuration of a two-system governor system of the prior application, and a graph showing its operation characteristics.
[Explanation of symbols]
1, 2 governor 3, 4 valve 5, 6 pilot valve 10 primary line 20 secondary line 40 detecting means 50 motor 60 controller 61 servo amplifier 62 pressure gauge 63 departure judging means 64 speed changing means

Claims (4)

Adjust the pressure regulator to supply the fluid supplied from the primary side to the secondary side while reducing the pressure and to maintain the predetermined secondary pressure against the fluctuating supply flow rate so that appropriate responsiveness is obtained. Pressure regulator control system,
Indicator detecting means for detecting an indicator reflecting the control operation of the pressure regulator,
Deviation determination means for determining the degree that the index detected by the index detection means deviates from a preset range within a period set in advance to a fluctuation cycle of the supply flow rate of the fluid,
Speed changing means for partially changing the response speed of control of the pressure regulator according to the degree of deviation determined by the deviation determining means in a direction in which the degree of deviation approaches a predetermined reference degree. A pressure regulator control system characterized by the following. A plurality of the pressure regulators operate simultaneously in parallel,
The pressure regulator control system according to claim 1, wherein at least one pressure regulator performs a control operation of a secondary pressure such that an operation state of another pressure regulator is within a predetermined range. The pressure regulator control system according to claim 1, wherein the index detection unit detects at least one of an opening degree and a pressure of the pressure regulator as the index. The pressure regulator control system according to any one of claims 1 to 3, wherein a response speed of the pressure regulator control is faster than an expected appropriate response speed.

Images