A solution and structure for delay of high liquid level signal in pickling tank

Abstract

The present invention relates to a solution and structure for preventing high-level signal delay in the pickling tank of large-scale steel strip pickling. The solution involves flushing the acid high-level detection probe in the pickling tank after shutting down and draining the acid, thereby eliminating surface crystallization of the probe after shutdown and, consequently, eliminating high-level signal delay. A flushing pipe is buried at the location where the acid high-level detection probe is installed in the pickling tank. During shutdown, residual acid on the surface of the probe is flushed away. The flushing time is 1 to 2 seconds, and the flushing pressure is 0.1 to 0.15 MPa. The present invention flushes the acid high-level detection probe in the pickling tank after shutting down and draining the acid, without interrupting the unit's effective production time. Using only a small amount of water, it does not dilute the pickling solution and can supplement acid evaporation during production. The present invention eliminates surface crystallization of the acid high-level detection probe in the pickling tank after shutdown, eliminating high-level signal delay, and increasing annual production by over 10,000 tons.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel pickling, and in particular to a solution and structure for delaying a high liquid level signal in a pickling tank. Background Art

[0002] like Figure 1 、 Figure 2 As shown in the figure, it is a process flow chart of the hot-rolled strip pickling process in a steel plant. The hot-rolled strip 4 passes through three pickling tanks filled with acid (1 # Pickling tanks 1 and 2 # Pickling tanks 2 and 3 # Pickling tank 3) removes surface iron oxide scale, and then passes through 4 rinsing tanks (1 # Rinse tank 5, 2 # Rinse tank 6, 3 # Rinse tank 7, 4 # The rinse water in the rinse tank 8) is sprayed to remove the residual acid on the surface. The operating condition of the pickling section strip is that the three pickling tanks meet the high liquid level signal.

[0003] During on-site implementation, when the production line breaks down or is shut down for maintenance, after the acid in the pickling tank is drained, the residual acid on the surface of the acid high-level detection probe 17 produces crystals. When the acid is filled again, it takes 2 minutes for the acid to dissolve the crystals around the acid high-level detection probe 17, giving a high liquid level detection signal, and the strip steel 4 can start running. Even if the time for troubleshooting and maintenance shutdown is taken into account, the normal cycle of roller change of the production line also needs to be shut down twice per shift, and 6 times per day for 3 shifts. The total downtime due to the delay of the pickling tank high liquid level signal is 64 hours based on 320 production days throughout the year. Conservatively calculated based on an output of 200 tons / hour, 12,800 tons of steel are produced less throughout the year. Therefore, the problem of the delay of the pickling tank high liquid level signal is what the present invention aims to solve. Summary of the Invention

[0004] The purpose of the present invention is to provide a solution and structure for the delay of the high liquid level signal of the pickling tank. After shutdown, the rinse water in the rinse tank is used to rinse the acid high level detection probe in the pickling tank to remove the residual acid on the surface of the probe, thereby avoiding crystallization of the probe after the acid in the pickling tank is emptied, thereby solving the problem of delay of the high liquid level signal of the acid in the pickling tank.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A solution to the problem of high liquid level signal delay in the pickling tank is to flush the acid high level detection probe in the pickling tank after shutting down the machine to drain the acid, thereby eliminating surface crystallization of the acid high level detection probe after the shutdown, and further eliminating the high liquid level signal delay phenomenon. The specific method is as follows:

[0007] 1) Bury the flushing pipe at the location where the acid high-level detection probe is installed in the pickling tank;

[0008] 2) Stop the machine to drain the acid, the pickling tank high liquid level signal is disconnected, and the pickling tank low liquid level signal is connected;

[0009] 3) Introduce the flushing liquid into the flushing pipe to flush away the acid remaining on the surface of the acid high-level detection probe;

[0010] 4) The flushing time is 1 to 2 seconds, and the flushing pressure is 0.1 to 0.15 MPa.

[0011] The flushing liquid in the flushing pipeline comes from the rinsing water in the rinse tank.

[0012] A solution to the high liquid level signal delay in a pickling tank adopts a structure including a flushing pipe and a flushing main pipe. One end of the flushing pipe is buried in the side wall of the pickling tank and connected to the protective cover of the acid high level detection probe. The other end of the flushing pipe is connected to the flushing main pipe, and the flushing main pipe is connected to the outlet of the rinsing circulation pump.

[0013] A control valve is installed on the flushing pipeline.

[0014] The diameter of the flushing pipe is 25 to 30 mm.

[0015] The diameter of the flushing main pipe is 50-60 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present invention flushes the acid high-level detection probe in the pickling tank after the machine is shut down for acid drainage. The flushing time is only 2 seconds, which does not occupy the effective production time of the unit.

[0018] 2) The present invention uses only a small amount of water. The water used for one flushing only accounts for 0.005-0.01% of the total acid solution, which does not dilute the pickling solution and can be used as a supplement for the evaporation of acid solution during production.

[0019] 3) The present invention eliminates the surface crystallization of the pickling tank acid high-level detection probe after shutdown, and completely eliminates the phenomenon of high liquid level signal delay after the pickling tank is filled, and the unit produces more than 10,000 tons per year. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the strip pickling flow chart.

[0021] Figure 2 This is a diagram of the liquid level detection in the strip pickling tank.

[0022] Figure 3 This is a top view of the strip pickling tank.

[0023] Figure 4 It is a schematic diagram of the side wall of the pickling tank.

[0024] Figure 5 It is a partial top view of the pickling tank of the present invention.

[0025] Figure 6 It is a structural schematic diagram of the present invention.

[0026] In the picture: 1-1 # Pickling tank, 2-2 # Pickling tank, 3-3 # Pickling tank, 4-strip steel, 5-1 # Rinse tank, 6-2 # Rinse tank, 7-3 # Rinse tank, 8-4 # Rinsing tank, 9-desalted water tank, 10-washing water tank, 11-3 # Pickling liquid circulation tank, 12-rinsing circulation pump, 13-2 # Pickling liquid circulation tank, 14-1 # Pickling liquid circulation tank, 15-transmission roller, 16-acid liquid low-level detection probe, 17-acid liquid high-level detection probe, 18-side wall of the pickling tank, 19-protective cover of the acid liquid high-level detection probe, 20-flushing pipe, 21-flushing main pipe, 22-control valve. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0028] like Figure 3-Figure 6 As shown, a solution to the delay of the high liquid level signal in the pickling tank is to flush the acid high level detection probe 17 in the pickling tank after the acid is shut down to drain, thereby eliminating the surface crystallization of the acid high level detection probe 17 after the shutdown, thereby eliminating the high liquid level signal delay phenomenon; the specific method is as follows:

[0029] 1) Bury the flushing pipe 20 at the location where the acid high-level detection probe 17 is installed in the pickling tank;

[0030] 2) Stop the machine to drain the acid, the pickling tank high liquid level signal is disconnected, and the pickling tank low liquid level signal is connected;

[0031] 3) Introducing the flushing liquid into the flushing pipe 20 to flush away the acid remaining on the surface of the acid high-level detection probe 17;

[0032] 4) The flushing time is 1 to 2 seconds, and the flushing pressure is 0.1 to 0.15 MPa.

[0033] The flushing liquid in the flushing pipe 20 comes from the rinsing water in the rinsing tank.

[0034] A solution to the high liquid level signal delay in a pickling tank adopts a structure including a flushing pipe 20 and a flushing main pipe 21. One end of the flushing pipe 20 is buried in the side wall 18 of the pickling tank and connected to the protective cover 19 of the acid high level detection probe. The other end of the flushing pipe 20 is connected to the flushing main pipe 21, and the flushing main pipe 21 is connected to the outlet of the rinsing circulation pump 12.

[0035] A control valve 22 is installed on the flushing pipe 20.

[0036] The diameter of the flushing pipe 20 is 25 to 30 mm.

[0037] The diameter of the flushing main pipe 21 is 50 to 60 mm.

[0038] Embodiments of the present invention:

[0039] The embodiment of the present invention is to connect the flushing main 21 to 1 # The outlet of the rinsing circulation pump 12 of the rinsing tank 5 is respectively at 1 # Pickling tanks 1 and 2 # Pickling tanks 2 and 3 # A flushing pipe 20 is buried in the side wall of the pickling tank 3 , one end of the flushing pipe 20 is connected to the protective cover 19 of the acid high-level detection probe, and the other end of the flushing pipe 20 is connected to the flushing main pipe 21 .

[0040] In the embodiment, the flushing pipe 20 is made of FRP material and is divided into two sections. One section of the flushing pipe 20 is buried in the side wall 18 of the pickling tank, and the other section of the flushing pipe 20 is outside the side wall 18 of the pickling tank and is connected to the flushing pipe 20 buried in the side wall 18 of the pickling tank through a flange water outlet. The flushing pipe 20 outside the side wall 18 of the pickling tank is connected to the flushing main pipe 21; the flushing pipes 20 all have a diameter of 30 mm.

[0041] The flushing main pipe 21 is made of FRP material and has a pipe diameter of 50 mm.

[0042] A control valve 22 is installed on each flushing pipe 20 leading to the pickling tank to control the water flow and flushing time.

[0043] Flushing process of the acid high level detection probe 17:

[0044] 1) The strip steel 4 stops running, all circulation pumps stop running, and the rinsing spray stops;

[0045] 2) Pickling tank (1 # Pickling tanks 1 and 2 # Pickling tanks 2 and 3 # Pickling tank 3) The acid is emptied and enters the acid circulation tank (1 # Pickling liquid circulation tank 14, 2 #Pickling liquid circulation tank 13, 3 # Pickling liquid circulation tank 11);

[0046] 3) The pickling tank high liquid level signal is disconnected;

[0047] 4) The low-level signal of the acid solution in the pickling tank is connected, and the control valve 22 is opened;

[0048] 5)1 # The rinsing circulation pump 12 of the rinsing tank 5 is turned on and running → the rinsing water of the 1# rinsing tank 5 enters the flushing main 21:

[0049] 6) Rinse water enters 1 # Pickling tanks 1 and 2 # Pickling tanks 2 and 3 # The acid high level detection probe in the pickling tank 3 is placed in the protective cover 19 to flush away the residual acid on the probe surface;

[0050] 7) 2 seconds later 1 # The rinsing circulation pump 12 of the rinsing tank 5 stops running, the control valve 22 is closed, and the rinsing is completed.

[0051] The flushing pressure of the embodiment is 0.1Mpa; the total flushing water flow rate is 8m 3 / h; the water consumption for one flush is 2.2~4.4L, which does not exceed 0.01% of the total acid solution volume.

Claims

1. A solution to the delay of high liquid level signal in pickling tank, characterized in that: This method involves flushing the acid high-level detection probe in the pickling tank after shutting down the machine to drain the acid, thereby eliminating surface crystallization on the acid high-level detection probe after shutdown and further eliminating the high-level signal delay phenomenon. The specific method is as follows: 1) Bury the flushing pipe at the location where the acid high-level detection probe is installed in the pickling tank; 2) Stop the machine to drain the acid, the pickling tank high level signal is disconnected, and the pickling tank low level signal is connected; 3) Introduce the flushing liquid into the flushing pipe to flush away the acid remaining on the surface of the acid high-level detection probe; 4) The flushing time is 1 to 2 seconds and the flushing pressure is 0.1 to 0.15 MPa; The solution to the high liquid level signal delay in the pickling tank adopts a structure including a flushing pipe and a flushing main pipe. One end of the flushing pipe is buried in the wall of the pickling tank and connected to the protective cover of the acid high level detection probe. The other end of the flushing pipe is connected to the flushing main pipe, and the flushing main pipe is connected to the outlet of the rinsing circulation pump.

2. A solution to the delay of the high liquid level signal in the pickling tank according to claim 1, characterized in that: The flushing liquid in the flushing pipeline comes from the rinsing water in the rinse tank.

3. A solution to the delay of the high liquid level signal in the pickling tank according to claim 1, characterized in that: A control valve is installed on the flushing pipeline.

4. A solution to the delay of the high liquid level signal in the pickling tank according to claim 1, characterized in that: The diameter of the flushing pipe is 25 to 30 mm.

5. A solution to the delay of the high liquid level signal in the pickling tank according to claim 1, characterized in that: The diameter of the flushing main pipe is 50-60 mm.

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