TRT Hydraulic Bypass Valve Dual Valve Position Detection System and Control Method

Abstract

A dual-valve position detection system and control method for a TRT hydraulic bypass valve. A rotary encoder is installed on the valve shaft rod to measure the rotation angle of the valve shaft rod. The feedback signal of the rotation angle of the valve shaft rod measured by the rotary encoder is connected to the PLC controller. Programming is carried out inside the PLC controller to judge whether the feedback signal is normal, and then the normal feedback signal value is sent to the servo controller. When the feedback signal X received by the PLC controller has a range of 0-100%, if X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, if; when both valve position signals are normal, the linear displacement sensor is used as the valve position feedback signal. Its advantages are that the dual-valve position detection of the TRT hydraulic bypass valve is realized, improving the reliability of valve operation; the on-line maintenance of the valve feedback signal failure is realized, reducing the shutdown time of the TRT and increasing the power generation; and the safety of TRT operation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical equipment, and particularly relates to a double-valve position detection system and control method for a TRT hydraulic bypass valve. Background Art

[0002] When the TRT is operating normally, the hydraulic bypass valve is generally in a fully closed state; when the TRT shuts down or the blast furnace gas volume is too large, the bypass valve participates in regulation to ensure the stability of the blast furnace top pressure. Currently, the valve position detection of the TRT bypass valve is achieved by installing a linear displacement sensor on the hydraulic cylinder of the actuator, and a set of valve position sensors is installed for one valve. In the actual use process, the following problems mainly exist:

[0003] 1. Once the valve position sensor fails, the valve will automatically open fully, and the adjustment function will be lost, resulting in the pressure relief of the blast furnace and the fluctuation of the top pressure, seriously affecting the production of the blast furnace. At the same time, if this fault needs to be handled, the TRT must be shut down, affecting the power generation.

[0004] 2. The valve position detects linear displacement, and there is a deviation between the indicated value and the actual angle of the valve. Summary of the Invention

[0005] The purpose of the present invention is to provide a double-valve position detection system and control method for a TRT hydraulic bypass valve that can achieve long-term accurate and reliable measurement of the bypass valve position and improve the operating stability of the bypass valve.

[0006] The solution of the present invention is as follows:

[0007] A double-valve position detection system for a TRT hydraulic bypass valve includes a linear displacement sensor, a hydraulic cylinder, a valve shaft rod, a servo controller, and a PLC controller. A rotary encoder is installed on the valve shaft rod to measure the rotation angle of the valve shaft rod; the feedback signal of the rotation angle of the valve shaft rod measured by the rotary encoder is connected to the PLC controller, and programming is carried out inside the PLC controller to judge whether the feedback signal is normal, and then the normal feedback signal value is sent to the servo controller. When the feedback signal X received by the PLC controller has a range of 0 - 100%, if X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback. When it is detected that the feedback signal of the linear displacement sensor is abnormal, it is automatically switched to the rotary encoder signal as the valve position feedback signal; if both valve position signals are normal, the linear displacement sensor is used as the valve position feedback signal.

[0008] A control method for a double-valve position detection system of a TRT hydraulic bypass valve includes the steps of:

[0009] (1) Valve rotation angle measurement step: Measure the valve rotation angle, and feedback the measured rotation angle signal to the PLC controller;

[0010] (2) Feedback signal abnormal judgment step: Set the feedback signal value as X, and the range is 0 - 100%. The PLC controller controls according to the feedback signal value X according to the following strategy:

[0011] 1) When X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback signal. When it is detected that the feedback signal of the linear displacement sensor is abnormal, it automatically switches to the rotary encoder signal as the valve position feedback signal;

[0012] 2) When both valve position signals are normal, use the linear displacement sensor as the valve position feedback signal;

[0013] (3) When the PLC controller determines that the feedback signal is normal, send the normal feedback signal value to the servo controller.

[0014] A more specific technical solution further includes: In the step (1), the method for measuring the rotation angle of the valve is: Install a rotary encoder on the valve shaft rod to measure the rotation angle of the valve shaft rod.

[0015] Further: The calculation method for measuring the rotation angle of the valve is:

[0016] L2 = L1 + L

[0017] According to the cosine theorem of a triangle, it can be obtained that:

[0018] L2 2 = R 2 + H 2 - 2RHcos(α + β)

[0019] After calculation, it is obtained that:

[0020]

[0021] Among them, L1, H, R, and α are constants. L1 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point when the valve is fully closed. H is the distance between the valve shaft rod and the fixed shaft of the hydraulic cylinder. R is the crank length. L2 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point of the valve when the valve is operating at a certain position. Assume that the indication value of the linear displacement sensor is L; After converting the linear displacement sensor into an angle signal, it can form a redundant detection system for valve position detection with the rotary encoder.

[0022] The advantages of the present invention are:

[0023] 1. The TRT hydraulic bypass valve realizes double valve position detection, improves the reliability of valve operation, and improves the operation stability of the bypass valve.

[0024] 2. Online maintenance of valve feedback signal faults is achieved, reducing the downtime of TRT and increasing power generation.

[0025] 3. The safety of TRT operation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the present invention.

[0027] Figure 2 It is a schematic diagram of the valve position conversion of the TRT hydraulic bypass valve of the present invention.

[0028] Figure 3 It is a schematic diagram of the double-valve position detection principle of the TRT hydraulic bypass valve of the present invention.

[0029] Figure 4 It is a schematic structural diagram of the TRT hydraulic bypass valve.

[0030] The details of the components in the drawings are as follows: linear displacement sensor 1, hydraulic cylinder 2, hydraulic cylinder fixed shaft 3, rotary encoder 4, valve shaft rod 5, fully open position of the valve 6, operating trajectory 7, fully closed position of the valve 8, valve 9, hydraulic drive device 10. DETAILED DESCRIPTION OF THE INVENTION

[0031] The double-valve position detection system of the TRT hydraulic bypass valve of the present invention realizes the double-valve position detection of the valve by installing two sets of valve position detection sensors on the hydraulic drive device. The specific method is as follows: adding 1 set of rotary encoders on the valve shaft rod, and combining with the originally supporting linear displacement sensor to realize redundant measurement of the valve opening.

[0032] Convert the linear displacement indication value of the valve position to an angular displacement indication value to truly feedback the indication value of the linear displacement sensor to the valve position, and at the same time be consistent with the valve position displayed by the rotary encoder.

[0033] The detailed structure of the present invention is as Figure 1 shown, including a linear displacement sensor 1, a hydraulic cylinder 2, a hydraulic cylinder fixed shaft 3, a valve shaft rod 5, a servo controller, and a PLC controller. When the valve rotates to the fully closed position 8 of the valve, it is in the valve closed state. When the valve rotates to the fully open position 6 of the valve, it is in the valve fully open state, and the valve operation forms an operating trajectory 7.

[0034] As Figure 4As shown in the figure, a rotary encoder 4 is installed on the valve shaft rod 5 to measure the rotation angle of the valve shaft rod 5. The feedback signal of the rotation angle of the valve shaft rod 5 measured by the rotary encoder 4 is connected to the PLC controller. Programming is carried out inside the PLC controller to judge whether the feedback signal is normal, and then the normal feedback signal value is sent to the servo controller. When the feedback signal X received by the PLC controller has a range of 0 - 100%, if X < -1% or X > 110%, or when the valve control signal (given signal) remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback. When it is detected that the feedback signal of the linear displacement sensor is abnormal, it automatically switches to the rotary encoder signal as the valve position feedback signal; if both valve position feedback signals are normal, the linear displacement sensor is used as the valve position feedback signal. By adding a set of rotary encoders on the valve shaft rod and combining with the original supporting linear displacement sensor, redundant measurement of the valve opening is realized.

[0035] As Figure 2 shown, the dimensions of the valve position at a certain position are as marked in the figure, where L1, H, R, and α are constants. L1 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point when the valve is fully closed, H is the distance between the valve shaft rod and the fixed shaft of the hydraulic cylinder, R is the crank length, and L2 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point of the valve when the valve is operating at a certain position. Assuming the indication value of the linear displacement sensor is L, then:

[0036] L2 = L1 + L

[0037] According to the cosine theorem of a triangle, we can get:

[0038] L2 2 = R 2 + H 2 - 2RHcos(α + β)

[0039] After calculation, we obtain:

[0040]

[0041] After converting the linear displacement sensor into an angular signal, it can form a redundant detection system for valve position detection with the rotary encoder.

[0042] As Figure 3 shown, a control method for a dual-valve position detection system of a TRT hydraulic bypass valve according to the present invention includes the steps:

[0043] (1) Valve rotation angle measurement step: Measure the valve rotation angle and feedback the measured rotation angle signal to the PLC controller; the method for measuring the valve rotation angle is: install a rotary encoder on the valve shaft rod to measure the rotation angle of the valve shaft rod;

[0044] (2)Feedback signal abnormal judgment steps: Set the feedback signal value as X, with a range of 0 - 100%. The PLC controller controls according to the feedback signal value X according to the following strategy:

[0045] 1) When X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback signal. When it is detected that the feedback signal of the linear displacement sensor is abnormal, it automatically switches to the rotary encoder signal as the valve position feedback signal;

[0046] 2) When both valve position feedback signals are normal, use the linear displacement sensor as the valve position feedback signal;

[0047] (3)When the PLC controller determines that the feedback signal is normal, send the normal feedback signal value to the servo controller.

[0048] The calculation method for measuring the valve rotation angle is as follows:

[0049] L2 = L1 + L

[0050] According to the cosine theorem of a triangle, we can get:

[0051] L2 2 = R 2 + H 2 - 2RHcos(α + β)

[0052] After calculation, we obtain:

[0053]

[0054] Among them, L1, H, R, and α are constants. L1 is the distance between the fixed axis of the hydraulic cylinder and the crank connection point when the valve is in the fully closed position. H is the distance between the valve shaft rod and the fixed axis of the hydraulic cylinder. R is the crank length. L2 is the distance between the fixed axis of the hydraulic cylinder and the crank connection point of the valve when the valve is in a certain position. Assume that the indication value of the linear displacement sensor is L; after converting the linear displacement sensor into an angle signal, it can form a redundant detection system for valve position detection with the rotary encoder.

[0055] Connect the 4 - 20mA feedback signals of the linear displacement sensor and the rotary encoder to the PLC. Program in the PLC to judge whether the feedback signal is normal, and then send the normal feedback signal value to the servo controller. The method for judging abnormal feedback signals (assuming the feedback signal value is X, with a range of 0 - 100%):

[0056] When X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%.

[0057] When both valve position feedback signals are normal, the linear displacement sensor is used as the valve position feedback signal. When the feedback signal of the linear displacement sensor is detected to be abnormal, it automatically switches to the rotary encoder signal as the valve position feedback signal.

[0058] The present invention has been tested in the 3#, 4#, and 5# blast furnace TRTs of Liugang Ironmaking Plant. Double valve position detection has been achieved for all hydraulic bypass valves. When any valve position sensor fails, automatic switching can be realized without affecting the normal operation of the valve, effectively improving the operation stability of the TRT.

Claims

1. A double-valve position detection system for a TRT hydraulic bypass valve, comprising a linear displacement sensor (1), a hydraulic cylinder (2), a valve shaft rod (5), a servo controller, a PLC controller, and a crank. The hydraulic cylinder (2) drives the valve shaft rod (5) to rotate through the crank, and the linear displacement sensor (1) is installed on the hydraulic cylinder (2). It is characterized in that: Install a rotary encoder (4) on the valve shaft rod (5) to measure the rotation angle of the valve shaft rod (5); connect the feedback signal of the rotation angle of the valve shaft rod (5) measured by the rotary encoder (4) to the PLC controller, program inside the PLC controller to judge whether the feedback signal is normal, and then send the normal feedback signal value to the servo controller. When the feedback signal X received by the PLC controller has a range of 0 - 100%, if X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback. When it is detected that the feedback signal of the linear displacement sensor is abnormal, automatically switch to the rotary encoder signal as the valve position feedback signal; if both valve position signals are normal, use the linear displacement sensor as the valve position feedback signal.

2. A control method for a dual-valve position detection system of a TRT hydraulic bypass valve as described in claim 1, characterized in that: It includes the steps: (1) Valve rotation angle measurement step: Measure the valve rotation angle and feedback the measured rotation angle signal to the PLC controller; (2) Abnormal feedback signal judgment step: Set the feedback signal value as X, with a range of 0 - 100%. The PLC controller controls according to the following strategy based on the feedback signal value X: 1) When X < -1% or X > 110%, or when the valve control signal remains unchanged and the feedback signal X fluctuates > 10%, it is an abnormal feedback signal. When it is detected that the feedback signal of the linear displacement sensor is abnormal, automatically switch to the rotary encoder signal as the valve position feedback signal; 2) When both valve position signals are normal, use the linear displacement sensor as the valve position feedback signal; (3) When the PLC controller determines that the feedback signal is normal, send the normal feedback signal value to the servo controller.

3. The control method of the double-valve-position detection system of the TRT hydraulic bypass valve according to claim 2, wherein: In the step (1), the method for measuring the valve rotation angle is: Install a rotary encoder (4) on the valve shaft rod (5) to measure the rotation angle of the valve shaft rod (5).

4. The control method of the double-valve-position detection system of the TRT hydraulic bypass valve according to claim 3, characterized in that: The calculation method for measuring the valve rotation angle is: L2 = L1 + L According to the cosine theorem of a triangle, it can be obtained that: L2 2 =R 2 +H 2 - 2RH cos(α + β) After calculation, it is obtained that: Where L1, H, R, and ɑ are constants. L1 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point when the valve is fully closed. H is the distance between the valve shaft rod and the fixed shaft of the hydraulic cylinder. R is the crank length. L2 is the distance between the fixed shaft of the hydraulic cylinder and the crank connection point of the valve when the valve is operating at a certain position; assume the indication value of the linear displacement sensor is L; after converting the linear displacement sensor into an angle signal, it can form a redundant detection system for valve position detection with the rotary encoder.

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