An automatic sewage discharge system and operation method for a compressed air system

Abstract

An automatic sewage draining system and operation method for a compressed air system. The system includes an air storage tank, a sewage draining pipe, a manual valve, a first electric valve and a second electric valve; the bottom of the air storage tank is communicated with the sewage draining pipe, and the other end of the sewage draining pipe is communicated with a drainage ditch. The manual valve, the first electric valve and the second electric valve are successively arranged on the sewage draining pipe, and a temperature measuring device is arranged at the inlet and outlet ports of the manual valve; a water accumulation alarm is arranged at the bottom of the air storage tank, and a pressure sensor is arranged at the top of the air storage tank. The pressure sensor, the water accumulation alarm, the first electric valve, the second electric valve and the temperature measuring device are connected to a PLC controller through signal lines, and the PLC controller is connected to a control cabinet through a signal line. In the present invention, a special sequence control process is designed on an independent PLC or a control cabinet, and a special control mechanism, an execution mechanism and a measurement feedback mechanism are configured, so as to achieve the purpose of fully automatic or manual sewage draining.

Description

Technical Field

[0001] The present invention relates to the field of air supply systems for hydropower stations, and particularly to an automatic sewage discharge system and operation method for a compressed air system. Background Art

[0002] The compressed air system of a hydropower station generally can be divided into a medium-pressure air system and a low-pressure air system. The medium-pressure air system is generally used for the oil pressure device of the governor, and the low-pressure air system is generally used for mechanical braking, enclosed busbars, and purging. In order to ensure the air supply quality (dryness, cleanliness) of the compressed air system, it is necessary to regularly discharge the sewage from the air storage tank in the compressed air system.

[0003] Since it is not easy to control the sewage discharge time of the fully automatic sewage discharge work, and it is difficult to quantitatively or qualitatively judge whether the sewage discharge is complete, most power stations still discharge the sewage of the compressed air system in the form of regular work and by manual methods, that is, the operator operates electrically on the touch screen of the control cabinet or operates purely manually on site. The above sewage discharge method causes great waste of human resources. Especially in the general trend of fewer or no people in hydropower stations, the above disadvantages will be more prominent. At the same time, due to the different skill levels, operating habits, and operating experiences of personnel, equipment damage may be caused during the sewage discharge process and the normal operation of the air system may be affected. Therefore, it is necessary to design an automatic sewage discharge system and operation method for the compressed air system to solve the above problems. Summary of the Invention

[0004] In view of the technical problems existing in the background art, the present invention provides an automatic sewage discharge system and operation method for a compressed air system. A special sequence control process is designed on an independent PLC or a combined control cabinet, and special control mechanisms, actuating mechanisms, and measurement (feedback) mechanisms are configured to achieve the purpose of fully automatic or manual sewage discharge.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve:

[0006] An automatic sewage discharge system and operation method for a compressed air system, the system includes an air storage tank, a sewage discharge pipe, a manual valve, a first electric valve, and a second electric valve; the bottom of the air storage tank is connected to a sewage discharge pipe, and the other end of the sewage discharge pipe is connected to a drainage ditch. The sewage discharge pipe is sequentially provided with a manual valve, a first electric valve, and a second electric valve, and a temperature measuring device is arranged at the inlet and outlet ports of the manual valve;

[0007] An accumulated water alarm is arranged at the bottom of the air storage tank, and a pressure sensor is arranged at the top of the air storage tank. The pressure sensor, the accumulated water alarm, the first electric valve, the second electric valve, and the temperature measuring device are connected to a PLC controller through signal lines, and the PLC controller is connected to a combined control cabinet through signal lines;

[0008] The operation process of the automatic sewage discharge system for the compressed air system is as follows:

[0009] Step 1. Under normal conditions, the manual valve remains partially open, the first electric valve and the second electric valve are closed, and the water accumulation alarm, pressure sensor inside the gas storage tank, and temperature measuring device on the outer wall of the drain pipe are operating normally; when the full-automatic drain preset conditions are met, that is, when the drain timing cycle arrives, or the water accumulation alarm activates, or a remote drain command is received, the operation process is immediately started.

[0010] Step 3. The PLC controller determines whether the conditions for the automatic drain system are met:

[0011] When the conditions for the automatic drain system are met, Step 3 is executed.

[0012] When the conditions for the automatic drain system are not met, the operation process is exited, and an alarm code is generated: the conditions for automatic drain are not met.

[0013] Step 3: The PLC controller issues a command to open the first electric valve and monitors the opening state of the first electric valve within a limited time:

[0014] When the first electric valve is normally opened within the limited time, Step 4 is executed.

[0015] When the first electric valve cannot be normally opened within the limited time, the operation process is exited, and an alarm code is generated: the first electric valve opening timeout.

[0016] Step 4: The PLC controller issues a command to open the second electric valve and monitors the opening state of the second electric valve within a limited time:

[0017] When the second electric valve is normally opened within the limited time, Step 5 is executed.

[0018] When the second electric valve cannot be normally opened within the limited time, this step and Step 5 are skipped and Step 6 is entered. At the same time, an alarm code is generated: the second electric valve opening timeout.

[0019] Step 5: The system starts the drain timing and performs a drain determination within a limited time:

[0020] When the drain determination conditions are met, the system starts to execute Step 6.

[0021] When the drain determination conditions are not met within the limited time, this step is skipped and Step 6 is entered. At the same time, an alarm code is generated: drain timeout exception.

[0022] Step 6: The PLC controller issues a command to close the first electric valve and monitors the closing state of the first electric valve within a limited time:

[0023] When the first electric valve is normally closed, Step 7 is executed.

[0024] If the first electric valve cannot be closed properly, skip this step and go to Step 7, and at the same time generate an alarm code: the first electric valve closing timeout;

[0025] Step 7: The PLC controller issues an instruction to close the second electric valve, and monitors the closing state of the second electric valve within a specified time:

[0026] When the second electric valve is closed properly, the operation process of the automatic sewage discharge system ends;

[0027] When the second electric valve cannot be closed properly, exit the operation process, and at the same time generate an alarm code: the second electric valve closing timeout.

[0028] In a preferred solution, the temperature measuring device includes an arc-shaped clamping plate, a temperature measuring patch and a connecting bolt; both ends of the arc-shaped clamping plate are connected by a connecting bolt, and a temperature measuring patch is pasted on the inner side of the arc-shaped clamping plate. The radian of the arc-shaped clamping plate and the temperature measuring patch is consistent with the outer diameter of the sewage discharge pipe. When the temperature measuring patch works, it is closely attached to the outer wall of the sewage discharge pipe and is clamped and fixed by the arc-shaped clamping plate.

[0029] In a preferred solution, in step 2, the following conditions must be met simultaneously to meet the conditions of the automatic sewage discharge system:

[0030] 1. The air system pressure is not lower than the alarm value; 2. There is no alarm in the air system; 3. The automatic control mode of the air system is automatic; 4. The first electric valve is fully closed and the power supply of the first electric valve has no fault; 5. The second electric valve is fully closed and the power supply of the second electric valve has no fault.

[0031] In a preferred solution, in step 5, when the temperature difference T measured by the temperature measuring devices at the front and rear ends of the manual valve is greater than the set value of the PLC controller, the sewage discharge determination condition can be met.

[0032] This patent can achieve the following beneficial effects:

[0033] 1. The present invention makes the sewage discharge work process-based, realizes the full automation of the air system sewage discharge through this system, and reduces the risk of manual operation;

[0034] 2. A fault protection jump function is set in the work process. When a fault occurs in the operation process of the automatic sewage discharge system, the system can take necessary protection measures and automatically jump to the next step or directly terminate the process, and at the same time issue a warning to remind the staff to handle the fault in time, avoiding equipment damage and affecting the normal operation of the air system;

[0035] 3. The present invention can effectively reduce the waste of human resources, create operating conditions for the advanced automation operation of the power station, and at the same time further reduce the operation and maintenance costs of the power station. Brief Description of the Drawings

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0037] Figure 1 This is the hardware composition diagram of the automatic sewage discharge system of the compressed air system of the present invention;

[0038] Figure 2 This is the structural schematic diagram of the temperature measuring device of the present invention;

[0039] Figure 3 This is the structural schematic of the temperature measuring device of the present invention Figure 2 ;

[0040] Figure 4 This is the start-up condition diagram of the automatic sewage discharge system of the present invention;

[0041] Figure 5 This is the operation flow chart of the automatic sewage discharge system of the compressed air system of the present invention.

[0042] In the figure: gas storage tank 1, temperature measuring device 2, arc-shaped splint 201, temperature measuring sticker 202, connecting bolt 203, manual valve 3, first electric valve 4, second electric valve 5, drainage ditch 6, water accumulation alarm 7, pressure sensor 8, PLC controller 9, control cabinet 10, sewage discharge pipe 11, signal line 12. Specific embodiments

[0043] As Figure 1 shown, an automatic sewage discharge system and operation method for a compressed air system, the system includes a gas storage tank 1, a sewage discharge pipe 11, a manual valve 3, a first electric valve 4 and a second electric valve 5; the bottom of the gas storage tank 1 is communicated with a sewage discharge pipe 11, and the other end of the sewage discharge pipe 11 is communicated with a drainage ditch 6. The sewage discharge pipe 11 is sequentially provided with a manual valve 3, a first electric valve 4 and a second electric valve 5, and a temperature measuring device 2 is arranged at the inlet and outlet ports of the manual valve 3;

[0044] When the system works, if the installation conditions are not met, only one of the first electric valve 4 and the second electric valve 5 can be selectively installed. The first electric valve 4 and the second electric valve 5 in the system adopt a redundant design of electric valve in series, aiming to ensure that the valves of the high-pressure gas system can be reliably closed;

[0045] A water accumulation alarm 7 is arranged at the bottom of the gas storage tank 1, and a pressure sensor 8 is arranged at the top of the gas storage tank 1. The pressure sensor 8, the water accumulation alarm 7, the first electric valve 4, the second electric valve 5 and the temperature measuring device 2 are connected to the PLC controller 9 through a signal line 12, and the PLC controller 9 is connected to the control cabinet 10 through a signal line 12.

[0046] The preferred scheme is as Figure 2 and Figure 3As shown in the figure, the temperature measuring device 2 includes an arc-shaped clamping plate 201, a temperature measuring sticker 202 and a connecting bolt 203; both ends of the arc-shaped clamping plate 201 are connected by the connecting bolt 203, and the temperature measuring sticker 202 is pasted on the inner side of the arc-shaped clamping plate 201. The radian of the arc-shaped clamping plate 201 and the temperature measuring sticker 202 is consistent with the outer diameter of the sewage discharge pipe 11. When the temperature measuring sticker 202 works, it is closely attached to the outer wall of the sewage discharge pipe 11 and is clamped and fixed by the arc-shaped clamping plate 201;

[0047] Adopting the above-mentioned hoop-type fixing structure, the temperature measuring device 2 can ensure that the temperature measuring sticker 202 can be fully attached to the outer wall of the sewage discharge pipe 11, which is beneficial to improving the response speed and measurement accuracy of the temperature measuring resistor. At the same time, this structure is simple to disassemble and install, and does not change the system structure of the sewage discharge pipe 11 during installation, with low cost and short cycle for technical improvement.

[0048] The preferred solution is as Figure 1 and Figure 4 shown. The principle for the system to realize sewage discharge determination is:

[0049] 1. Under normal conditions, the manual valve 3 remains partially open (the opening degree can be adjusted according to actual needs), and the first electric valve 4 and the second electric valve 5 are closed. After reaching the sewage discharge cycle set by the PLC controller 9 or when the water accumulation alarm acts, the PLC controller 9 issues an order to open the first electric valve 4 and the second electric valve 5 in sequence to start sewage discharge;

[0050] 2. At this time, the liquid flowing through the partially open manual valve 3, the temperature of the temperature measuring device 2 is equivalent to the ambient temperature, and the temperature difference ΔT0 is close to zero;

[0051] 3. When the sewage discharge is completed, the gas flows through the partially open manual valve 3, and the gas expands and absorbs heat at the manual valve 3, resulting in a large temperature difference ΔT1 before and after the valve;

[0052] 4. When the temperature difference ΔT1 reaches the set value ΔT2 of the PLC controller 9, a command to open and close the electric valve is issued after a delay, and the first electric valve 4 and the second electric valve 5 are closed, and the sewage discharge process ends;

[0053] When the temperature difference ΔT1 does not reach the set value ΔT2 within the specified time, the PLC controller 9 issues an abnormal alarm for sewage discharge timeout and issues a command to open and close the electric valve to close the first electric valve 4 and the second electric valve 5; at the same time, if the pressure in the gas storage tank is lower than the alarm set value during the sewage discharge process, in order to avoid further pressure reduction affecting the gas supply object, the PLC controller 9 issues a command to urgently close the first electric valve 4 and the second electric valve 5.

[0054] Automatic sewage discharge system of compressed air system, Automatic sewage discharge example 1:

[0055] Step 1: The manual valve 3 remains in a partially open state, the first electric valve 4 and the second electric valve 5 are in the closed state, the water accumulation alarm 7 and the pressure sensor 8 inside the air storage tank 1, and the temperature measuring device 2 on the outer wall of the sewage discharge pipe 11 are operating normally; when the full-automatic sewage discharge preset conditions are met, that is, when the sewage discharge timing cycle arrives, or the water accumulation alarm 7 activates, or a remote sewage discharge instruction is received, the operation process is immediately started.

[0056] Step 2: The PLC controller 9 judges the conditions of the automatic sewage discharge system. If it is found that the conditions of the automatic sewage discharge system are not met, the system exits the operation process at this time and generates an alarm code: the conditions for automatic sewage discharge are not met.

[0057] Automatic sewage discharge example 2 of the compressed air system automatic sewage discharge system:

[0058] Step 1: The manual valve 3 remains in a partially open state, the first electric valve 4 and the second electric valve 5 are in the closed state, the water accumulation alarm 7 and the pressure sensor 8 inside the air storage tank 1, and the temperature measuring device 2 on the outer wall of the sewage discharge pipe 11 are operating normally; when the full-automatic sewage discharge preset conditions are met, that is, when the sewage discharge timing cycle arrives, or the water accumulation alarm 7 activates, or a remote sewage discharge instruction is received, the operation process is immediately started.

[0059] Step 2: The PLC controller 9 judges the conditions of the automatic sewage discharge system. If it is found that the conditions of the automatic sewage discharge system are met, it immediately executes Step 3.

[0060] Step 3: The PLC controller 9 issues an instruction to open the first electric valve 4. The first electric valve 4 can operate normally within the specified time (set to 30 s) and immediately executes Step 4.

[0061] Step 4: The PLC controller 9 issues an instruction to open the second electric valve 5. If the second electric valve 5 cannot be opened normally within the specified time (set to 30 s), this step and Step 5 are skipped and Step 6 is entered. At the same time, an alarm code is generated: the opening of the second electric valve 5 times out.

[0062] Step 6: The PLC controller 9 issues an instruction to close the first electric valve 4. The first electric valve 4 can operate normally within the specified time (set to 30 s) and immediately executes Step 7.

[0063] Step 7: The PLC controller 9 issues an instruction to close the second electric valve 5. The second electric valve 5 can operate normally within the specified time (set to 30 s), and the operation process of the automatic sewage discharge system ends.

[0064] Automatic sewage discharge example 3 of the compressed air system automatic sewage discharge system:

[0065] Step 1: The manual valve 3 remains in a partially open state, the first electric valve 4 and the second electric valve 5 are in a closed state, the water accumulation alarm 7 and the pressure sensor 8 inside the gas storage tank 1 and the temperature measuring device 2 on the outer wall of the drain pipe 11 are operating normally; when the full-automatic drainage preset conditions are met, that is, when the drainage timing cycle arrives, or the water accumulation alarm 7 operates, or a remote drainage command is received, the operation process is immediately started.

[0066] Step 2: The PLC controller 9 judges the conditions of the automatic drainage system. If it is found that the conditions of the automatic drainage system are met, Step 3 is immediately executed.

[0067] Step 3: The PLC controller 9 issues an instruction to open the first electric valve 4. The first electric valve 4 can operate normally within the specified time (set to 45 s), and Step 4 is immediately executed.

[0068] Step 4: The PLC controller 9 issues an instruction to open the second electric valve 5. The second electric valve 5 can be normally opened within the specified time (set to 45 s), and Step 5 is immediately executed.

[0069] Step 5: The system starts the drainage timing and conducts drainage judgment within the specified time (set to 10 min). When it is found that the drainage judgment conditions are met, Step 6 is delayed for execution.

[0070] Step 6: The PLC controller 9 issues an instruction to close the first electric valve 4. If the first electric valve 4 cannot be normally closed within the specified time (set to 45 s), the system skips this step and enters Step 7, and at the same time generates an alarm code: the first electric valve 4 closing timeout.

[0071] Step 7: The PLC controller 9 issues an instruction to close the second electric valve 5. The second electric valve 5 can operate normally within the specified time (set to 45 s), and the automatic drainage system exits the operation process.

[0072] Example 4 of the automatic drainage of the compressed air system's automatic drainage system:

[0073] Step 1: The manual valve 3 remains in a partially open state, the first electric valve 4 and the second electric valve 5 are in a closed state, the water accumulation alarm 7 and the pressure sensor 8 inside the gas storage tank 1 and the temperature measuring device 2 on the outer wall of the drain pipe 11 are operating normally; when the full-automatic drainage preset conditions are met, that is, when the drainage timing cycle arrives, or the water accumulation alarm 7 operates, or a remote drainage command is received, the operation process is immediately started.

[0074] Step 2: The PLC controller 9 judges the conditions of the automatic drainage system. If it is found that the conditions of the automatic drainage system are met, Step 3 is immediately executed.

[0075] Step 3: The PLC controller 9 issues an instruction to open the first electric valve 4. The first electric valve 4 can operate normally within a limited time (set to 20 s) and immediately execute Step 4;

[0076] Step 4: The PLC controller 9 issues an instruction to open the second electric valve 5. The second electric valve 5 can be normally opened within a limited time (set to 20 s) and immediately execute Step 5;

[0077] Step 5: The system starts sewage discharge timing and conducts sewage discharge determination within a limited time. It is found that the system does not meet the sewage discharge determination conditions within the limited time (set to 6 min). At this time, this step is skipped and Step 6 is entered, and an alarm code is generated: sewage discharge timeout exception;

[0078] Step 6: The PLC controller 9 issues an instruction to close the first electric valve 4. The first electric valve 4 can operate normally within a limited time (set to 20 s) and immediately execute Step 7;

[0079] Step 7: The PLC controller 9 issues an instruction to close the second electric valve 5. The second electric valve 5 can operate normally within a limited time (set to 20 s), and the automatic sewage discharge system exits the operation process.

[0080] The above embodiments are only the preferred technical solutions of the present invention and should not be regarded as limitations on the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, the equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An operation method for an automatic sewage discharge system of a compressed air system. The system includes an air storage tank (1), a sewage discharge pipe (11), a manual valve (3), a first electric valve (4), and a second electric valve (5); characterized in that: A drain pipe (11) is connected to the bottom of the gas storage tank (1), and the other end of the drain pipe (11) is connected to a drainage ditch (6). A manual valve (3), a first electric valve (4) and a second electric valve (5) are successively installed on the drain pipe (11), and a temperature measuring device (2) is installed at the inlet and outlet ports of the manual valve (3). A water accumulation alarm (7) is provided at the bottom of the gas storage tank (1), and a pressure sensor (8) is installed at the top of the gas storage tank (1). The pressure sensor (8), the water accumulation alarm (7), the first electric valve (4), the second electric valve (5) and the temperature measuring device (2) are connected to a PLC controller (9) through signal lines (12), and the PLC controller (9) is connected to a control cabinet (10) through signal lines (12). The operation process of the automatic drainage system of the compressed air system is as follows: Step1: Under normal conditions, the manual valve (3) remains partially open, the first electric valve (4) and the second electric valve (5) are in the closed state, and the water accumulation alarm (7) and the pressure sensor (8) inside the gas storage tank (1) and the temperature measuring device (2) on the outer wall of the drain pipe (11) operate normally; when the drainage timing period arrives, or the water accumulation alarm (7) operates, or a remote drainage command is received, the operation process is immediately started. Step2: The PLC controller (9) judges whether the conditions of the automatic drainage system are met: When the conditions of the automatic drainage system are met, Step3 is executed. When the conditions of the automatic drainage system are not met, the operation process is exited, and an alarm code is generated: the conditions for automatic drainage are not met. Step3: The PLC controller (9) issues an instruction to open the first electric valve (4), and monitors the opening state of the first electric valve (4) within a specified time: When the first electric valve (4) is normally opened within the specified time, Step4 is executed. When the first electric valve (4) cannot be normally opened within the specified time, the operation process is exited, and an alarm code is generated: the first electric valve (4) opening timeout. Step4: The PLC controller (9) issues an instruction to open the second electric valve (5), and monitors the opening state of the second electric valve (5) within a specified time: When the second electric valve (5) is normally opened within the specified time, Step5 is executed. When the second electric valve (5) cannot be normally opened within the specified time, this step and Step5 are skipped and Step6 is entered, and at the same time an alarm code is generated: the second electric valve (5) opening timeout. Step5: The system starts drainage timing and performs drainage determination within a specified time: When the drainage determination condition is reached, the system starts to execute Step6. When the drainage determination condition is not reached within the specified time, this step is skipped and Step6 is entered, and at the same time an alarm code is generated: drainage timeout exception. Step6: The PLC controller (9) issues an instruction to close the first electric valve (4), and monitors the closing state of the first electric valve (4) within a specified time: When the first electric valve (4) is normally closed, Step7 is executed. When the first electric valve (4) cannot be normally closed, this step is skipped and Step7 is entered, and at the same time an alarm code is generated: the first electric valve (4) closing timeout. Step 7: The PLC controller (9) issues an instruction to close the second electric valve (5), and monitors the closing state of the second electric valve (5) within a specified time: When the second electric valve (5) is normally closed, the operation process of the automatic sewage draining system ends; When the second electric valve (5) cannot be normally closed, the operation process is exited, and an alarm code is generated: the second electric valve (5) closing timeout; In step 5, the sewage draining determination condition can be met only when the temperature difference T measured by the temperature measuring devices (2) at the front and rear ends of the manual valve (3) is greater than the set value of the PLC controller (9).

2. The operation method of the automatic sewage discharge system of the compressed air system according to claim 1, characterized in that: The temperature measuring device (2) includes an arc-shaped clamping plate (201), a temperature measuring sticker (202) and a connecting bolt (203); both ends of the arc-shaped clamping plate (201) are connected by the connecting bolt (203), and the temperature measuring sticker (202) is pasted on the inner side of the arc-shaped clamping plate (201). The radian of the arc-shaped clamping plate (201) and the temperature measuring sticker (202) is consistent with the outer diameter of the sewage draining pipe (11). When the temperature measuring sticker (202) works, it closely adheres to the outer wall of the sewage draining pipe (11) and is clamped and fixed by the arc-shaped clamping plate (201).

3. The operating method of the automatic sewage discharge system of the compressed air system according to claim 1, characterized in that: In step 2, the following points must be met simultaneously to meet the conditions of the automatic sewage draining system: 1), The air system pressure is not lower than the alarm value; 2), The air system has no alarm; 3), The automatic control mode of the air system is automatic; 4), The first electric valve (4) is fully closed and the power supply of the first electric valve (4) has no fault; 5), The second electric valve (5) is fully closed and the power supply of the second electric valve (5) has no fault.

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