CN216484179U - Automatic purging system for fan stall sampling device - Google Patents
Automatic purging system for fan stall sampling device Download PDFInfo
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- CN216484179U CN216484179U CN202122771174.6U CN202122771174U CN216484179U CN 216484179 U CN216484179 U CN 216484179U CN 202122771174 U CN202122771174 U CN 202122771174U CN 216484179 U CN216484179 U CN 216484179U
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Abstract
The utility model relates to an automatic purging system for a fan stall sampling device, wherein the fan stall sampling device comprises a stall probe and an A, B sampling tube; the automatic purging system comprises a differential pressure transmitter, an A, B purging branch, a A, B isolation control branch, a first isolation electromagnetic valve and a second isolation electromagnetic valve which are respectively arranged on the A, B isolation control branch, and a third purging electromagnetic valve and a fourth purging electromagnetic valve which are respectively arranged on the A, B purging branch; and the differential pressure transmitter is in communication connection with the DCS. The DCS is used as a control core, the purging electromagnetic valve and the isolating electromagnetic valve are additionally arranged, the opening and closing of each electromagnetic valve are controlled by utilizing a time sequence, the release and the investment of stall protection during purging are automatically realized, manual intervention is not needed, the periodic purging of a stall sampling pipeline can be safely, efficiently and reliably completed, the sampling pipeline is kept smooth, and the conditions of protection failure and misoperation are avoided; the method can save manpower, avoid protection refusal and misoperation caused by human factors, and is suitable for popularization.
Description
Technical Field
The utility model relates to the technical field of fan stall protection, in particular to an automatic purging system for a fan stall sampling device.
Background
The thermal power plant fan stall protection is an important auxiliary machine protection for preventing the fan from being damaged, and the reliability of the stall protection action depends on whether a stall sampling measurement loop is normal or not.
In order to prevent the fan from being damaged when stall occurs and influence the safe operation of a unit, a stall probe is installed on an air duct shell right above an adjusting blade of a general axial flow fan, the stall probe is connected to a differential pressure transmitter through a sampling pipe, and then a signal is sent to a DCS (distributed control system) to be subjected to out-of-limit logical judgment.
Generally, the A hole of the stall probe is connected with a high-pressure hole (H hole) of the micro differential pressure transmitter, and the B hole is connected with a low-pressure hole (L hole). In normal operation, the B orifice pressure is greater than the A orifice pressure, i.e. PB > PA, and increases with increasing load (flow); but when the fan stalls, the pressure of the hole A is greater than that of the hole B, namely PA is greater than PB. However, when the bucket installation angle is small (about 10 degrees), the a hole pressure is larger than the B hole pressure even in a normal case, and the operation is generally performed while avoiding the opening. And when the DCS system detects that the stall differential pressure A hole is larger than the B hole and exceeds 200Pa, tripping the fan by delaying 100 seconds. The stall probe measurement schematic is shown in fig. 1.
The medium that flows in the fan of thermal power plant is not clean gas, often has a large amount of dust or dust, and the adhesion nature of dust is strong moreover, inevitably adheres to on the whole wind smoke system pipeline all the time. For accurate measurement, the aperture of the opening on the two sides of the stall probe is generally very small, about 3mm in diameter, and the stall probe is very easy to adhere and block by dust or fine dust.
If stall sampling lines are all blocked, or the degree of blockage of the hole A is greater than that of the hole B, stall protection is lost; if the two measuring holes are not blocked uniformly, for example, the blocking degree of the hole B is greater than that of the hole A, the measured pressure of the hole A is greater than that of the hole B, the DCS misjudges that stall occurs, and protection misoperation occurs. The above-mentioned conditions of refusing action and false action can be avoided only by keeping the sampling pipeline unblocked.
Therefore, thermal power plants generally incorporate periodic purging of the sampling and measurement lines into periodic work, with purging being performed substantially once a month, and in winter, with the supply air thermal cycle turned on, the frequency of purging is reduced to once a week. According to the requirements of safety regulation process, a work order to be handled is purged every time, stall protection is applied to be removed, then a measuring pipeline of a differential pressure transmitter is disconnected, and 2 persons cooperate to dredge a sampling pipeline by using temporary compressed air. And after dredging is finished, the measurement pipeline connection is recovered, and finally stall protection and ticket refunding are applied. The whole work takes about 4 hours for two people.
In the whole manual purging work, the following defects exist: 1) labor is consumed; 2) in the process of releasing and putting into stall protection, protection misoperation or refusal operation is caused by human factors; 3) when the sampling pipelines on the two sides of the differential pressure transmitter are recovered after purging, the possibility of confusion exists on the two sides A, B, and protection misoperation or refusal is caused.
SUMMERY OF THE UTILITY MODEL
The utility model mainly aims to overcome the defects of the prior art, and provides an automatic purging system for a fan stall sampling device, which can safely, efficiently and reliably complete the periodic purging of a stall sampling pipeline without manual intervention, keep the sampling pipeline smooth, avoid the conditions of protection rejection and misoperation, save manpower, avoid the protection rejection and misoperation caused by human factors, and is suitable for popularization in a thermal power plant.
The utility model adopts the following technical scheme:
an automatic purging system for a fan stall sampling device comprises a stall probe with a detection hole A and a detection hole B, a sampling tube A communicated with the detection hole A and a sampling tube B communicated with the detection hole B; the automatic purging system comprises a differential pressure transmitter, an A purging branch, an A isolating control branch, a B purging branch, a B isolating control branch, a first isolating electromagnetic valve, a second isolating electromagnetic valve, a third purging electromagnetic valve and a fourth purging electromagnetic valve, wherein one end of the A purging branch is connected with an A sampling pipe, the other end of the A purging branch is used for being connected with a compressed air source, one end of the A isolating control branch is connected with the A sampling pipe, the other end of the A purging branch is connected with a high-pressure hole of the differential pressure transmitter, one end of the B purging branch is connected with a B sampling pipe, the other end of the B purging branch is used for being connected with the compressed air source, one end of the B isolating control branch is connected with the B sampling pipe, and the other end of the B purging control branch is connected with a low-pressure hole of the differential pressure transmitter; the first and second isolation solenoid valves are respectively used for controlling the on-off of a pipeline between the A, B sampling tube and the differential pressure transmitter; the third purging electromagnetic valve and the fourth purging electromagnetic valve are respectively used for controlling the on-off of a pipeline between the A, B sampling tube and the compressed air source; the differential pressure transmitter is in communication connection with the DCS, and control ends of the first isolation electromagnetic valve, the second isolation electromagnetic valve, the third purging electromagnetic valve and the fourth purging electromagnetic valve are respectively connected to a digital quantity output clamping piece of the DCS.
Furthermore, the automatic purging system for the fan stall sampling device further comprises a compressed air main pipeline, one end of the compressed air main pipeline is communicated with the purging branch A and the purging branch B, the other end of the compressed air main pipeline is used for being connected with a compressed air source, and a fifth main electromagnetic valve is arranged on the compressed air main pipeline and used for controlling the connection and disconnection of pipelines between the compressed air source and the purging branch A, B; and the control end of the fifth main electromagnetic valve is connected to a digital quantity output card of the DCS.
Furthermore, the DCS is provided with an electromagnetic valve control function module which comprises a starting/ending purging and cutting/putting-in protection control loop, an isolating electromagnetic valve opening/closing control loop and a purging process control loop; the output of the electromagnetic valve control function module is connected with and controls a first isolation electromagnetic valve, a second isolation electromagnetic valve, a third purging electromagnetic valve, a fourth purging electromagnetic valve and a fifth general electromagnetic valve through a digital quantity output clamping piece of the DCS.
Further, the start/end purge and cut/put protection control loop includes a start/end purge and cut protection control loop and a put protection control loop; the start/end purging and cutting protection control loop comprises an automatic purging starting module, a first RS trigger, a first pulse module, a first delay module, a purging control module and a start protection module, wherein the output end of the automatic purging starting module is connected to the input end of the first pulse module, the output end of the first pulse module is connected to the set input end of the first RS trigger, the input end of the first delay module is connected with the output end of the first RS trigger, the output end of the first delay module is connected to the reset input end of the first RS trigger, and the output end of the first RS trigger is connected to the purging control module and the cutting protection module; the input protection control loop comprises an AND gate, a second delay module and an input protection module, wherein two input ends of the AND gate are respectively connected with a purging state signal and a stall differential pressure normal signal, the output end of the AND gate is connected with the input end of the second delay module, the output end of the second delay module is connected to the input protection module, and the AND gate is configured to output a high level when the purging state is the purging completion and the stall differential pressure is normal.
Furthermore, the isolation solenoid valve opening/closing control loop comprises a second RS trigger, a third delay module, a second pulse module and a fourth delay module, wherein the input end of the third delay module is connected with the output end of the excision protection module, the output end of the third delay module is connected to the input end of the second pulse module, the output end of the second pulse module is connected to the set input end of the second RS trigger, the input end of the fourth delay module is connected to the output end of the second RS trigger, the output end of the fourth delay module is connected to the reset input end of the second RS trigger, and the output end of the second RS trigger is connected with and controls the first and second isolation solenoid valves.
Furthermore, the purging process control loop comprises a third RS trigger, a third pulse module, a fifth delay module, a sixth delay module, a seventh delay module, a first purging module and a second purging module, wherein the input end of the fifth delay module is connected with the output end of the second RS trigger, the output end of the fifth delay module is connected with the input end of the third pulse module, the output end of the third pulse module is connected to the set input end of the third RS trigger, the input end of the sixth delay module is connected with the output end of the third RS trigger, the output end of the sixth delay module is connected to the reset input end of the third RS trigger, the output end of the third RS trigger is connected with and controls a fifth general electromagnetic valve, the third purging electromagnetic valve is connected and controlled through the first purging module, and the fourth purging electromagnetic valve is controlled through the seventh delay module and the second purging module in sequence.
Further, the first purging module and the second purging module respectively comprise a fourth RS trigger, a fourth pulse module, an eighth delay module and a plurality of intermittent purging control branches, the plurality of intermittent purging control branches respectively comprise a branch delay module and a branch pulse module, the output end of the branch delay module is connected with the input end of the branch pulse module, the output end of the third RS trigger is connected to the fourth pulse module, the input ends of the eighth delay module and the branch delay modules of the plurality of intermittent purging control branches, the output end of the fourth pulse module is connected to the set input end of the fourth RS trigger, the output end of the eighth delay module is connected to the reset input end of the fourth RS trigger, and the output end of the fourth RS trigger and the output ends of the branch pulse modules of the plurality of intermittent purging control branches are connected to the third purging electromagnetic valve or the fourth purging electromagnetic valve.
Further, the first isolation solenoid valve and the second isolation solenoid valve are normally open solenoid valves; the third purging electromagnetic valve, the fourth purging electromagnetic valve and the fifth general electromagnetic valve are normally closed electromagnetic valves.
Furthermore, the first isolation solenoid valve, the second isolation solenoid valve, the third purging solenoid valve, the fourth purging solenoid valve and the fifth general solenoid valve are two-position two-way solenoid valves.
Furthermore, the first isolation electromagnetic valve, the second isolation electromagnetic valve, the third purging electromagnetic valve, the fourth purging electromagnetic valve and the fifth main electromagnetic valve are respectively connected to a digital quantity output card of the DCS through control cables.
As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are:
firstly, the DCS is used as a control core, the purging electromagnetic valve and the isolating electromagnetic valve are additionally arranged, the opening and closing of each electromagnetic valve are controlled by utilizing a time sequence, the release and the investment of stall protection during purging are automatically realized, the automatic purging without manual intervention can be realized, the regular purging work of a stall sampling pipeline can be safely, efficiently and reliably completed, the sampling pipeline is kept smooth, and the conditions of protection failure and misoperation are avoided; meanwhile, the device is also beneficial to reducing the labor intensity of workers, and can solve the problems of labor consumption, and protection misoperation and failure caused in the process of removing, putting into protection or recovering the pipeline in the process of manual blowing.
Secondly, the fifth master electromagnetic valve is additionally arranged on the purging pipeline, so that the third purging electromagnetic valve and the fourth purging electromagnetic valve can be prevented from generating compressed air internal leakage, and measurement errors or stall protection misoperation can be avoided;
thirdly, the third purging electromagnetic valve and the fourth purging electromagnetic valve are purged intermittently, namely manual pulse purging is simulated, the instant impact force of compressed air can be utilized, circulation is carried out for many times, dust with strong adhesion is shaken thoroughly, and the purging effect is improved;
fourthly, before purging, stall protection can be automatically removed, and protection misoperation is avoided; after purging, whether the stall differential pressure of the measurement loop is normal or not can be automatically judged, stall protection is automatically put into the measurement loop when the stall differential pressure is normal, and stall protection is put into the measurement loop after inspection and treatment when the stall differential pressure is not normal, so that the operation reliability can be improved;
fifthly, the electromagnetic valve adopts a two-position two-way electromagnetic valve to control the on-off of the pipeline, and has the advantages that: firstly, the use is safe, no dynamic seal exists, and the leakage is easy to stop; secondly, the control is simple and the price is low; thirdly, the size is small, the action is fast, the power is small, the response time of the electromagnetic valve can be as short as several milliseconds, only the action needs to be triggered, and no power is consumed at ordinary times;
sixthly, the investment cost is low, all hardware only needs about 1 ten thousand yuan, and the method is a direction for developing an intelligent power plant in the future and is suitable for popularization in the thermal power plant; the utility model can also be used for purging other flue gas differential pressure sampling pipelines or furnace negative pressure sampling pipelines with protection, and the number of DCS channels and electromagnetic valves can be properly adjusted according to actual needs.
Drawings
FIG. 1 is a schematic structural diagram of a prior art fan stall protection device;
FIG. 2 is a schematic structural diagram of an automatic purging system for a fan stall sampling device according to an embodiment of the present invention;
FIG. 3 is an overall flow diagram of an automatic purge in accordance with an embodiment of the present invention;
FIG. 4 is a control logic diagram of a start/end purge and cut/plunge protection control loop according to an embodiment of the present invention;
FIG. 5 is a control logic diagram for an isolation solenoid ON/OFF control loop in accordance with an embodiment of the present invention;
FIG. 6 is a control logic diagram of a purge process control loop in accordance with an embodiment of the present invention.
In the figure: 1. the device comprises a fan air cylinder, 2 a stall probe, 3.A sampling tube, 4.B sampling tube, 5. differential pressure transmitter, 6. control cable, 7.A purging branch, 8.B purging branch, 9.A isolation control branch, 10.B isolation control straight branch and 11. compressed air main pipeline.
Detailed Description
The utility model is further described below by means of specific embodiments.
Example 1
Referring to fig. 1 to 6, the automatic purging system for the fan stall sampling device of the present invention includes a stall probe 2 having a detection hole a and a detection hole B mounted on a fan drum 1, a sampling tube a 3 communicated with the detection hole a, and a sampling tube B4 communicated with the detection hole B. The automatic purging system comprises a differential pressure transmitter 5, an A purging branch 7 with one end connected with an A sampling pipe 3 and the other end used for being connected with a compressed air source, an A isolation control branch 9 with one end connected with the A sampling pipe 3 and the other end connected with a high-pressure hole of the differential pressure transmitter 5, a B purging branch 8 with one end connected with a B sampling pipe 4 and the other end used for being connected with the compressed air source, a B isolation control branch 10 with one end connected with the B sampling pipe 4 and the other end connected with a low-pressure hole of the differential pressure transmitter 5, a compressed air main pipeline 11 with one end communicated with the A purging branch 7 and the B purging branch 8 and the other end used for being connected with the compressed air source, a first isolation electromagnetic valve V1 and a second isolation electromagnetic valve V2 respectively arranged on the A purging branch 9 and the B isolation control branch 10, and a third purging electromagnetic valve V3 respectively arranged on the A purging branch 7 and the B purging branch 8, A fourth purge solenoid valve V4, and a fifth main solenoid valve V5 disposed on the compressed air main line 11; the first isolation electromagnetic valve V1 and the second isolation electromagnetic valve V2 are respectively used for controlling the on-off of pipelines between the sampling pipe A3 and the sampling pipe B4 and the differential pressure transmitter 5; the third purging electromagnetic valve V3 and the fourth purging electromagnetic valve V4 are respectively used for controlling the connection and disconnection of pipelines between the sampling pipe A3 and the sampling pipe B4 and a compressed air source; and the fifth master electromagnetic valve V5 is used for controlling the on-off of the pipelines between the compressed air source and the A purging branch 7 and the B purging branch 8. And the differential pressure transmitter 5 is in communication connection with the DCS system. And the control ends of the first isolation electromagnetic valve V1, the second isolation electromagnetic valve V2, the third purging electromagnetic valve V3, the fourth purging electromagnetic valve V4 and the fifth main electromagnetic valve V5 are respectively connected to a digital quantity output card of the DCS through control cables 6. The first isolation solenoid valve V1 and the second isolation solenoid valve V2 are normally open solenoid valves; the third purge solenoid valve V3, the fourth purge solenoid valve V4, and the fifth master solenoid valve V5 are normally closed solenoid valves. The first isolation solenoid valve V1, the second isolation solenoid valve V2, the third purge solenoid valve V3, the fourth purge solenoid valve V5 and the fifth main solenoid valve V5 are two-position two-way solenoid valves.
The DCS is provided with an electromagnetic valve control function module which comprises a starting/ending purging and cutting/putting-in protection control loop, an isolating electromagnetic valve opening/closing control loop and a purging process control loop. The output of the electromagnetic valve control function module is connected with and controls a first isolation electromagnetic valve V1, a second isolation electromagnetic valve V2, a third purging electromagnetic valve V3, a fourth purging electromagnetic valve V4 and a fifth main electromagnetic valve V5 through a digital quantity output card of the DCS.
The start/end purge and cut/plunge protection control loop includes a start/end purge and cut protection control loop and a plunge protection control loop. The start/finish purging and cutting protection control loop comprises an automatic purging starting module, a first RS trigger, a first pulse module, a first delay module, a purging control module and a start protection module, wherein the output end of the automatic purging starting module is connected to the input end of the first pulse module, the output end of the first pulse module is connected to the set input end of the first RS trigger, the input end of the first delay module is connected with the output end of the first RS trigger, the output end of the first delay module is connected to the reset input end of the first RS trigger, and the output end of the first RS trigger is connected to the purging control module and the cutting protection module. The input protection control loop comprises an AND gate, a second delay module and an input protection module, wherein two input ends of the AND gate are respectively connected with a purging state signal and a stall differential pressure normal signal, the output end of the AND gate is connected with the input end of the second delay module, the output end of the second delay module is connected to the input protection module, and the AND gate is configured to output a high level when the purging state is the purging completion and the stall differential pressure is normal. The automatic purging starting module can be realized by controlling a key or time delay; the cutting protection module is used for controlling cutting of the DCS stall protection; and the input protection module is used for controlling the input DCS system to stall and protect.
The control logic for the start/end purge and cut/plunge protection control loops is shown in fig. 4. Protection by excision: after purging is started, 2-second pulse is sent to trigger a first RS trigger, the output of Q1 is 1, purging is started, and protection cutting is carried out at the same time; 198 seconds later, i.e. the purging is finished, the first RS trigger is automatically reset. Investment protection: after purging is finished, the measured stall differential pressure is normal (within +/-50 Pa), protection is put into operation after 20 seconds of delay, and protection misoperation is avoided.
The isolation electromagnetic valve opening/closing control loop comprises a second RS trigger, a third delay module, a second pulse module and a fourth delay module, wherein the input end of the third delay module is connected with the output end of the excision protection module, the output end of the third delay module is connected to the input end of the second pulse module, the output end of the second pulse module is connected to the set input end of the second RS trigger, the input end of the fourth delay module is connected with the output end of the second RS trigger, the output end of the fourth delay module is connected to the reset input end of the second RS trigger, and the output end of the second RS trigger is connected with and controls the first isolation electromagnetic valve V1 and the second isolation electromagnetic valve V2.
The control logic for the isolation solenoid open/close control loop is shown in FIG. 5. After protection is cut off, delaying for 3 seconds, sending 2-second pulses to trigger a second RS trigger, outputting 1 by Q2, and closing a first isolation electromagnetic valve V1 and a second isolation electromagnetic valve V2; when the third purging solenoid valve V3, the fourth purging solenoid valve V5 and the fifth main solenoid valve V5 complete purging and are in a closed state, that is, after the first isolation solenoid valve V1 and the second isolation solenoid valve V2 are closed for 195 seconds, the second RS trigger is reset, and the first isolation solenoid valve V1 and the second isolation solenoid valve V2 are opened to enter a sampling state.
The purging process control loop comprises a third RS trigger, a third pulse module, a fifth delay module, a sixth delay module, a seventh delay module, a first purging module and a second purging module, wherein the input end of the fifth delay module is connected with the output end of the second RS trigger, the output end of the fifth delay module is connected with the input end of the third pulse module, the output end of the third pulse module is connected with the set input end of the third RS trigger, the input end of the sixth delay module is connected with the output end of the third RS trigger, the output end of the sixth delay module is connected with the reset input end of the third RS trigger, the output end of the third RS trigger is connected with and controls a fifth general electromagnetic valve V5, the first purging module is connected and controls a third purging electromagnetic valve V3, and the seventh delay module and the second purging module sequentially control a fourth purging electromagnetic valve V4. The second purging module comprises a fourth RS trigger, a fourth pulse module, an eighth delay module and six intermittent purging control branches, the six intermittent purging control branches comprise a branch delay module and a branch pulse module respectively, the output end of the branch delay module is connected with the input end of the branch pulse module, the output end of the third RS trigger is connected to the fourth pulse module, the eighth delay module and the input ends of the branch delay modules of the six intermittent purging control branches, the output end of the fourth pulse module is connected to the set input end of the fourth RS trigger, the output end of the eighth delay module is connected to the reset input end of the fourth RS trigger, the output end of the fourth RS trigger and the output ends of the branch pulse modules of the six intermittent purging control branches are connected to a third purging electromagnetic valve V3 or a fourth purging electromagnetic valve V4.
The control logic for purging the process control loop is shown in FIG. 6. After the first isolation electromagnetic valve V1 and the second isolation electromagnetic valve V2 are closed, 3 seconds are delayed, 2 seconds of pulse is sent to trigger the third RS trigger, the Q3 outputs 1, the fifth general electromagnetic valve V5 is opened, the third purging electromagnetic valve V3 is opened or the A side is continuously purged for 60 seconds through the packaged first purging module, the fourth RS trigger is reset after 60 seconds, six rounds of purging are carried out for 3 seconds, 2 seconds of intermittent purging are closed, the total time is 30 seconds, and the total time is 90 seconds for the A side purging. After 90 seconds, the third purge solenoid valve V3 is closed, and then the second purge module opens the fourth purge solenoid valve V4, and the same continuous purge for 60 seconds and the intermittent purge for 30 seconds as those of the a side are performed, and the purge for the B side is completed, and the fourth purge solenoid valve V4 is closed. After 180 seconds, the third RS trigger is reset, and the fifth main solenoid valve V5 is closed.
Referring to fig. 1 to 6, the whole purging process of the automatic purging system for the fan stall sampling device of the present invention is as follows:
when an operator presses a start automatic purging button or reaches the periodic purging time, the DCS automatically completes the following steps:
s1, starting purging to trigger the first RS trigger, entering a purging start link, and automatically removing the stall protection of the DCS, as shown in figure 4;
s2, delaying for 3 seconds (3 seconds of delay is reserved for the action of the solenoid valves in each step below to prevent the differential pressure transmitter from being damaged due to the cross action of the solenoid valves), closing the first isolation solenoid valve V1 and the second isolation solenoid valve V2, and stopping sampling of the differential pressure transmitter, wherein the step is shown in figure 5;
s3, delaying for 3 seconds, and automatically opening a fifth master electromagnetic valve V5, as shown in figure 6;
s4, opening a third purging electromagnetic valve V3, and continuously purging the stall probe A sampling tube 3 for 60 seconds;
s5, followed by a 30 second intermittent purge with the third purge solenoid valve V3 (simulating a manual one-loose-one-tight pulse purge with a leather hose, i.e., every 3 seconds of purge, closing the V3 purge solenoid valve for 2 seconds, cycling 6 times);
s6, then closing the third purge solenoid valve V3, delaying for 3 seconds, opening the fourth purge solenoid valve V4, executing a second purge module identical to the first purge module of the third purge solenoid valve V3, continuously purging the stall probe B sampling tube 4 for 60 seconds, then intermittently purging for 30 seconds;
s7, delaying for 3 seconds later, closing the fourth purging electromagnetic valve V4, and delaying for 3 seconds again to close the fifth main electromagnetic valve V5;
s8, opening the first isolation solenoid valve V1 and the second isolation solenoid valve V2 after delaying for 3 seconds, and recovering the smooth sampling pipeline of the differential pressure transmitter;
s9, after purging is finished, delaying for 20 seconds, judging that the measured differential pressure value is within +/-50 Pa (namely stall differential pressure is normal) by the DCS, and finally automatically putting into stall protection; if the stall measurement value is not within +/-50 Pa, an alarm is sent out on a DCS picture to remind an operator to check the stall sampling system; the entire intelligent purge process takes 218 seconds.
The utility model can also be used for purging other flue gas differential pressure sampling pipelines or furnace negative pressure sampling pipelines with protection, and the number of DCS channels and electromagnetic valves can be properly adjusted according to actual needs.
Example 2
This example differs from example 1 in that: the fifth master electromagnetic valve V5 is not arranged, and the A purging branch 7 and the B purging branch 8 are respectively connected with a compressed air source. The solenoid valve control function also removes control of the fifth master solenoid valve V5 accordingly.
The above description is only two specific embodiments of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by the design concept should fall within the scope of infringing the present invention.
Claims (10)
1. An automatic purging system for a fan stall sampling device, characterized in that: the fan stall sampling device comprises a stall probe with a detection hole A and a detection hole B, a sampling tube A communicated with the detection hole A and a sampling tube B communicated with the detection hole B; the automatic purging system comprises a differential pressure transmitter, an A purging branch, an A isolating control branch, a B purging branch, a B isolating control branch, a first isolating electromagnetic valve, a second isolating electromagnetic valve, a third purging electromagnetic valve and a fourth purging electromagnetic valve, wherein one end of the A purging branch is connected with an A sampling pipe, the other end of the A purging branch is used for being connected with a compressed air source, one end of the A isolating control branch is connected with the A sampling pipe, the other end of the A purging branch is connected with a high-pressure hole of the differential pressure transmitter, one end of the B purging branch is connected with a B sampling pipe, the other end of the B purging branch is used for being connected with the compressed air source, one end of the B isolating control branch is connected with the B sampling pipe, and the other end of the B purging control branch is connected with a low-pressure hole of the differential pressure transmitter; the first and second isolation solenoid valves are respectively used for controlling the on-off of a pipeline between the A, B sampling tube and the differential pressure transmitter; the third purging electromagnetic valve and the fourth purging electromagnetic valve are respectively used for controlling the on-off of a pipeline between the A, B sampling tube and the compressed air source; the differential pressure transmitter is in communication connection with the DCS, and control ends of the first isolation electromagnetic valve, the second isolation electromagnetic valve, the third purging electromagnetic valve and the fourth purging electromagnetic valve are respectively connected to a digital quantity output clamping piece of the DCS.
2. An automatic purging system for a fan stall sampling device as defined in claim 1, wherein: the compressed air main pipeline is communicated with the purging branch circuit A and the purging branch circuit B at one end, the other end of the compressed air main pipeline is used for connecting a compressed air source, and a fifth main electromagnetic valve is arranged on the compressed air main pipeline and used for controlling the connection and disconnection of pipelines between the compressed air source and the purging branch circuit A, B; and the control end of the fifth main electromagnetic valve is connected to a digital quantity output card of the DCS.
3. An automatic purging system for a fan stall sampling device as defined in claim 2, wherein: the DCS is provided with an electromagnetic valve control function module which comprises a starting/ending purging and cutting/putting-in protection control loop, an isolating electromagnetic valve opening/closing control loop and a purging process control loop; the output of the electromagnetic valve control function module is connected with and controls a first isolation electromagnetic valve, a second isolation electromagnetic valve, a third purging electromagnetic valve, a fourth purging electromagnetic valve and a fifth general electromagnetic valve through a digital quantity output clamping piece of the DCS.
4. An automatic purging system for a fan stall sampling device as defined in claim 3, wherein: the start/end purging and cutting/putting-in protection control loop comprises a start/end purging and cutting protection control loop and a putting-in protection control loop; the start/end purging and cutting protection control loop comprises an automatic purging starting module, a first RS trigger, a first pulse module, a first delay module, a purging control module and a start protection module, wherein the output end of the automatic purging starting module is connected to the input end of the first pulse module, the output end of the first pulse module is connected to the set input end of the first RS trigger, the input end of the first delay module is connected with the output end of the first RS trigger, the output end of the first delay module is connected to the reset input end of the first RS trigger, and the output end of the first RS trigger is connected to the purging control module and the cutting protection module; the input protection control loop comprises an AND gate, a second delay module and an input protection module, wherein two input ends of the AND gate are respectively connected with a purging state signal and a stall differential pressure normal signal, the output end of the AND gate is connected with the input end of the second delay module, the output end of the second delay module is connected to the input protection module, and the AND gate is configured to output a high level when the purging state is the purging completion and the stall differential pressure is normal.
5. An automatic purging system for a fan stall sampling device as defined in claim 4, wherein: the isolation electromagnetic valve opening/closing control loop comprises a second RS trigger, a third delay module, a second pulse module and a fourth delay module, wherein the input end of the third delay module is connected with the output end of the excision protection module, the output end of the third delay module is connected to the input end of the second pulse module, the output end of the second pulse module is connected to the set input end of the second RS trigger, the input end of the fourth delay module is connected with the output end of the second RS trigger, the output end of the fourth delay module is connected to the reset input end of the second RS trigger, and the output end of the second RS trigger is connected with and controls the first and second isolation electromagnetic valves.
6. An automatic purging system for a fan stall sampling device as defined in claim 5, wherein: the purging process control loop comprises a third RS trigger, a third pulse module, a fifth delay module, a sixth delay module, a seventh delay module, a first purging module and a second purging module, wherein the input end of the fifth delay module is connected with the output end of the second RS trigger, the output end of the fifth delay module is connected with the input end of the third pulse module, the output end of the third pulse module is connected to the set input end of the third RS trigger, the input end of the sixth delay module is connected with the output end of the third RS trigger, the output end of the sixth delay module is connected to the reset input end of the third RS trigger, the output end of the third RS trigger is connected with and controls a fifth general electromagnetic valve, the third purging electromagnetic valve is connected and controlled through the first purging module, and the fourth purging electromagnetic valve is controlled through the seventh delay module and the second purging module in sequence.
7. An automatic purging system for a fan stall sampling device as defined in claim 6, wherein: the first and second purging modules comprise a fourth RS trigger, a fourth pulse module, an eighth delay module and a plurality of interrupted purging control branches, the plurality of interrupted purging control branches comprise a branch delay module and a branch pulse module respectively, the output end of the branch delay module is connected with the input end of the branch pulse module, the output end of the third RS trigger is connected to the fourth pulse module, the eighth delay module and the input ends of the branch delay modules of the plurality of interrupted purging control branches, the output end of the fourth pulse module is connected to the set input end of the fourth RS trigger, the output end of the eighth delay module is connected to the reset input end of the fourth RS trigger, and the output end of the fourth RS trigger and the output ends of the branch pulse modules of the plurality of interrupted purging control branches are connected to the third purging electromagnetic valve or the fourth purging electromagnetic valve.
8. An automatic purging system for a fan stall sampling device as defined in claim 2, wherein: the first isolation electromagnetic valve and the second isolation electromagnetic valve are normally open electromagnetic valves; the third purging electromagnetic valve, the fourth purging electromagnetic valve and the fifth general electromagnetic valve are normally closed electromagnetic valves.
9. An automatic purging system for a fan stall sampling device as defined in claim 2, wherein: the first isolation electromagnetic valve, the second isolation electromagnetic valve, the third purging electromagnetic valve, the fourth purging electromagnetic valve and the fifth general electromagnetic valve are two-position two-way electromagnetic valves.
10. An automatic purging system for a fan stall sampling device as defined in claim 2, wherein: the first isolation electromagnetic valve, the second isolation electromagnetic valve, the third purging electromagnetic valve, the fourth purging electromagnetic valve and the fifth main electromagnetic valve are connected to a digital quantity output clamping piece of the DCS system through control cables respectively.
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| CN116422449A (en) * | 2023-03-28 | 2023-07-14 | 国能河北龙山发电有限责任公司 | Control method and device for coal mill material level purging system, electronic equipment and storage medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116422449A (en) * | 2023-03-28 | 2023-07-14 | 国能河北龙山发电有限责任公司 | Control method and device for coal mill material level purging system, electronic equipment and storage medium |
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