Automatic control method of improved diaphragm plate-and-frame filter press

Abstract

The invention discloses an automatic control method of an improved diaphragm plate-and-frame filter press, which comprises the following steps: S1, after a machine head is pressed, opening a feed valve and a first control valve of a water replenishing pipe of a squeezing water tank, and adjusting a switch by a second control valve according to the liquid level of the water tank; the feeding pump is manually started, and when the feeding pressure reaches a set value, the feeding pump automatically stops, and the feeding valve and the first control valve are closed; s2, closing a squeezing water return valve, starting a squeezing water pump, opening a squeezing pump outlet one-way valve and a squeezing pump, after squeezing is finished, stopping the squeezing water pump, closing the squeezing pump outlet one-way valve, opening the squeezing water return valve, and measuring and controlling a water tank return valve and a discharge valve according to an online turbidity meter; the device has the beneficial effects that sludge is effectively prevented from blocking a compressed air pipeline, when it is detected that the water quality is abnormal, squeezed water containing sludge can be automatically drained to a pit, and the vicious circle that filter plate diaphragms are damaged due to recycling of the squeezed water is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of plate and frame filter presses, in particular to an improved automatic control method for a diaphragm plate and frame filter press. Background Art

[0002] The diaphragm plate and frame filter press, an ideal filtration device for solid-liquid separation, primarily consists of expandable filter plates with filtrate passages arranged alternately in parallel with filter frames. Each set of filter plates and filter frames is sandwiched with filter cloth, which is compressed by a compression plate to form a filter press chamber. High-water sludge flows in through the feed inlet, undergoes secondary extrusion and dehydration, and the filtrate is diverted out through the filter plates. The filter residue is trapped on the filter cloth within the frame, accumulating into a cake. Once the filter plates and frame are loosened, the cake easily falls off. The overall system offers advantages such as simple operation, high cake solidification rate, and strong applicability, and is now widely used in wastewater treatment.

[0003] However, during actual operation, it was found that the backflush system and the pressing system of the equipment still have some hidden dangers, which can easily lead to major failures. On the one hand, the feed port of the device is connected to the backflush hole. Due to excessive pressure during feeding and pressing, the interception valve at the backflush hole has limited pressure resistance, which can easily cause internal leakage of the valve and blockage of the ventilation duct by materials. On the other hand, after the pressing process, the diaphragm filter press often directly returns the water flow to the pressing water tank for recycling. When a filter plate diaphragm is damaged and the pressed water is mixed with sludge, it is easy to puncture multiple diaphragms under the action of high pressure when it circulates to the next pressing, forming a vicious cycle. Once these hidden dangers occur, it is very difficult to detect and solve the problems, which will undoubtedly greatly increase the operating cost of the equipment and reduce the production efficiency of the equipment. For this reason, we propose an improved automatic control method for diaphragm plate and frame filter press. Summary of the Invention

[0004] The purpose of the present invention is to provide an improved automatic control method for a diaphragm plate and frame filter press to solve the hidden dangers of a vicious cycle of compressed air pipeline blockage and filter plate and diaphragm damage during operation of the existing diaphragm plate and frame filter press.

[0005] To achieve the above-mentioned purpose, an improved automatic control method for a diaphragm plate and frame filter press comprises the following steps:

[0006] S1. After the die head is tightened, open the feed valve and the first control valve of the squeeze water tank water supply pipe, and adjust the second control valve according to the water tank liquid level; manually start the feed pump. When the feed pressure reaches the set value, the feed pump automatically stops and closes the feed valve and the first control valve;

[0007] S2. Close the squeeze water reflux valve, start the squeeze water pump and open the squeeze pump outlet check valve. After squeezing, stop the squeeze water pump and close the squeeze pump outlet check valve. Open the squeeze water reflux valve and measure and control the water tank reflux valve and the discharge valve according to the online turbidity meter.

[0008] S3, open the sludge backflow valve, close the backflush emptying valve, open the backflush pneumatic valve, and the backflush check valve is automatically opened; after the backflush is completed, the backflush pneumatic valve is closed, the backflush check valve is automatically closed, and the backflush emptying valve is opened;

[0009] S4, the head is pre-loosened, the liquid collecting plate is opened, and the head is loosened after the head is loosened; the unloading program is started by manual intervention, and the head is compressed and the liquid collecting plate is closed after the unloading is completed.

[0010] As preferred, the feed pump and the pressing pump are both variable frequency pumps.

[0011] As preferred, the water tank is supplemented by a water supplement pipe, which is jointly controlled by the first control valve and the second control valve during the water supplement process, and the water supplement pipe is inserted into the top end of the outer wall of the water tank, the first control valve is installed on the side away from the water tank supplement hole and is interlocked with the plate frame machine feed valve, and the second control valve is installed on the side close to the water tank supplement hole and is controlled by the radar liquid level meter control switch arranged on the top of the water tank cavity.

[0012] As preferred, the detection probe of the online turbidity meter is fixed on the pressing water flow inlet main pipe, the turbidity sensor is arranged on the detection probe, and the detection probe is connected to the central processor of the control system through a wireless communication module; the central processor includes a data receiving module, a data analysis module and an alarm control module, the data analysis module sets the turbidity critical value as NTU, and the alarm control module is connected to the alarm light of the control system display screen.

[0013] As preferred, the backflow valve controls the inlet of the backflow pipeline, the backflow pipeline is a three-way pipeline, one side outlet is controlled by the water tank backflow valve and introduced into the pressing water tank, and the other side outlet is controlled by the external discharge valve and leads to the ditch; the opening and closing of the water tank backflow valve and the external discharge valve are both measured and controlled by the online turbidity meter, when the backflow water turbidity is ≤NTU, the external discharge valve is closed and the water tank backflow valve is opened; when the backflow water turbidity is >NTU, the water tank backflow valve is closed and the external discharge valve is opened, and an alarm signal is triggered at the same time.

[0014] As preferred, the backflush pneumatic valve and the backflush check valve are connected to the backflush end of the sludge supply pipeline in sequence through flanges, and the outlet direction of the backflush check valve faces the backflush end; one end of the backflush pneumatic valve is communicated with the compressed air pipe network, the other end of the backflush pneumatic valve is communicated with the inlet end of the backflush check valve, and the backflush check valve and the backflush pneumatic valve are both used to prevent sludge from entering the air pipeline.

[0015] As preferred, the backflush emptying valve controls the emptying pipe, the emptying pipe is connected between the backflush pneumatic valve and the backflush check valve to form a T-shaped pipeline, which is used to guide out the sludge when the backflush pneumatic valve is damaged and to alarm.

[0016] As preferred, the feed valve, the first control valve, the second control valve, the sludge backflow valve, the press water backflow valve, the water tank backflow valve, the external discharge valve and the backflushing emptying valve are all pneumatic valves, and all the pneumatic valves are provided with cables and air sources.

[0017] As preferred, the specific mode of the press pump in the step S is that the press pump frequency is adjusted according to real-time pressure feedback to maintain constant press pressure.

[0018] As preferred, the opening time of the backflushing pneumatic valve and the compressed air pressure value in the step S are both preset by the control system, and the backflushing pneumatic valve is automatically closed and the backflushing emptying valve is automatically started to release pressure after the backflushing is completed.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. In the feeding and pressing process, the backflushing emptying valve is kept open, and when the sludge supply channel pressure is too large to destroy the backflushing control valve, the backflushing one-way valve can still play an intercepting role, thereby guiding the sludge out of the emptying pipe, on the one hand ensuring the smoothness of the compressed air pipeline, and on the other hand enhancing the visualization of fault alarm, so that the valve can be repaired in time.

[0021] 2. In the present application, the press water backflow is first detected by an online turbidity meter, and when the data analysis module analyzes that the detection value is greater than the critical value, the water flow is collected into a ditch and reused after treatment, thereby avoiding the vicious cycle of filter plate diaphragm damage and outputting an alarm signal through the alarm control module to timely inform the staff to repair the damaged diaphragm. In addition, two control valves jointly control the press water tank water supply pipe, so that the automatic water supply process is performed during the feeding period, fully considering the water flow backflow and external discharge, and ensuring the rationality and effectiveness of the automatic water supply of the water tank.

[0022] 3. The present application can ensure the stable operation of the equipment by manually opening the feed pump by observing the working conditions of the concentration tank and the filter press. The whole working process has high automation degree, saves manual labor time and improves production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 The present application is a method flowchart.

[0024] Fig. 2 The present application is a schematic diagram.

[0025] Wherein: 1, feed valve; 2, feed pump; 3, first control valve; 4, second control valve; 5, press pump outlet check valve; 6, press water backflow valve; 7, press pump; 8, sludge backflow valve; 9, back flushing emptying valve; 10, back flushing pneumatic valve; 11, back flushing check valve; 12, back flushing end; 13, emptying pipe; 14, feed end; 15, water replenishing pipe; 16, online turbidity meter; 17, exhaust port; 18, ditch; 19, control system; 20, water tank; 61, water tank backflow valve; 62, external discharge valve. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0027] Please refer to Figs. 1-2 The present application provides a technical solution: improved diaphragm plate-and-frame filter press automatic control method, comprising the following steps:

[0028] S1, after the head is pressed tightly, the first control valve 3 of the feed valve 1 and the press water tank 20 water replenishing pipe 15 is opened, and the second control valve 4 is adjusted according to the water tank 20 liquid level switch; the feed pump 2 is started manually, and when the feed pressure reaches the set value, the feed pump 2 is automatically stopped and the feed valve 1 and the first control valve 3 are closed.

[0029] It should be noted that this step is the feeding stage of the diaphragm plate-and-frame filter press automatic control, specifically: the operator starts the head pressing program through the control system to make the head of the diaphragm plate-and-frame filter press tightly pressed, after the head is pressed tightly, the control system automatically opens the first control valve 3 of the feed valve 1 and the press water tank 20 water replenishing pipe 15, at this time, the second control valve 4 adjusts the switch state according to the liquid level of the water tank 20, the water replenishing pipe 15 of the water tank 20 is inserted at the top of the outer wall of the water tank 20, the first control valve 3 is installed away from the water replenishing hole of the water tank 20 and is interlocked with the plate-and-frame filter press feed valve 1, when the feed valve 1 is opened, the first control valve 3 is also opened; the second control valve 4 is installed close to the water replenishing hole of the water tank 20, the water level in the water tank 20 is monitored in real time by the radar liquid level meter arranged at the top of the outer cavity of the water tank 20, and the switch is controlled according to the preset liquid level range, the feed pump 2 is started manually, and the feed pump 2 starts to deliver the material to be treated into the diaphragm plate-and-frame filter press, in the feeding process, the pressure sensor monitors the feed pressure in real time and transmits the pressure signal to the control system. When the feed pressure reaches the set value, the control system automatically stops the feed pump 2 and closes the feed valve 1 and the first control valve 3, and the feeding stage is completed.

[0030] S2, close the press water reflux valve 6, start the press water pump and open the press pump outlet check valve 5, use the press pump 7, after the press is finished, stop the press water pump and close the press pump outlet check valve 5, open the press water reflux valve 6, according to the online turbidity instrument 16, control the water tank reflux valve 61 and the external discharge valve 62.

[0031] It should be noted that step S2 is the pressing stage of the present application, specifically: after the feeding is finished, the control system closes the press water reflux valve 6, starts the press water pump, and at the same time opens the press pump outlet check valve 5, the press pump 7 starts to work, and the press water is transported to the diaphragm of the diaphragm plate frame filter press, and the filter cake is pressed, a variable frequency constant pressure control mode is used to control the press pump 7, so as to ensure the stability of the pressure in the pressing process, the pressure sensor is used to monitor the pressing pressure in real time, and the signal is fed back to the control system, the control system adjusts the speed of the press pump 7 according to the feedback signal, after the pressing is finished, the control system stops the press water pump, and the press pump outlet check valve 5 is automatically closed. Then open the press water reflux valve 6, at this time the online turbidity instrument 16 starts to work. The detection probe of the online turbidity instrument 16 is fixed on the press water inlet main pipe, the turbidity sensor is arranged on the detection probe, and the turbidity data is transmitted to the central processor of the control system 19 through the wireless communication module. The central processor includes a data receiving module, a data analysis module and an alarm control module, and the data analysis module sets the turbidity critical value to 1 NTU. According to the online turbidity instrument 16, control the water tank reflux valve 61 and the external discharge valve 62: when the reflux water turbidity is less than or equal to 1 NTU, the external discharge valve 62 is closed and the water tank reflux valve 61 is opened, and the press water is refluxed to the press water tank 20; when the reflux water turbidity is greater than 1 NTU, the water tank reflux valve 61 is closed and the external discharge valve 62 is opened, and at the same time the alarm control module is connected to the alarm lamp of the display screen of the control system 19, the alarm signal is triggered, and the operator is reminded to handle.

[0032] S3, open the sludge reflux valve 8, close the back flushing emptying valve 9, open the back flushing pneumatic valve 10, and the back flushing check valve 11 is automatically opened; after the back flushing is finished, the back flushing pneumatic valve 10 is closed, the back flushing check valve 11 is automatically closed, and the back flushing emptying valve 9 is opened.

[0033] It should be noted that step S3 is the back flushing stage of the present application, specifically: the control system opens the sludge backflow valve 8, closes the back flushing emptying valve 9, and opens the back flushing pneumatic valve 10. The back flushing pneumatic valve 10 and the back flushing check valve 11 are sequentially connected to the back flushing end 12 of the sludge supply pipeline through flanges, the outlet direction of the back flushing check valve 11 is towards the back flushing end 12; one end of the back flushing pneumatic valve 10 is in communication with the compressed air pipe network, and the other end is in communication with the inlet end of the back flushing check valve 11. When the back flushing pneumatic valve 10 is opened, the back flushing check valve 11 is automatically opened, and the compressed air enters the back flushing end 12 of the sludge supply pipeline through the back flushing pneumatic valve 10 and the back flushing check valve 11 to clean the sludge in the pipeline; the compressed air forms a reverse air flow in the pipeline, blows the sludge attached to the inner wall of the pipeline and the filter plate back to the sludge pool, prevents the sludge from blocking the pipeline and the filter plate, and after the back flushing is completed, the control system closes the back flushing pneumatic valve 10, the back flushing check valve 11 is automatically closed, and the back flushing emptying valve 9 is opened to discharge the sludge that may be left in the pipeline during the back flushing. The back flushing emptying valve 9 controls the emptying pipe 13, the emptying pipe 13 is connected between the back flushing pneumatic valve 10 and the back flushing check valve 11 to form a T-shaped pipeline, which is used to guide the sludge out and indicate the warning when the back flushing pneumatic valve 10 is damaged.

[0034] S4, the head is pre-loosened, the liquid collecting plate is opened, the head is loosened, and then unloading is waited; manual intervention starts the unloading program, the head is compressed after unloading is completed, and the liquid collecting plate is closed.

[0035] It should be noted that step S4 is the unloading stage of the present application, specifically: the control system controls the head to be pre-loosened, and simultaneously opens the liquid collecting plate, after the head is completely loosened, the equipment enters a state of waiting for unloading, at this time, the operator can observe the dryness and thickness of the filter cake and the like, and judge whether unloading operation can be performed, manual intervention starts the unloading program, the unloading device starts to work, the filter cake is unloaded from the filter plate, after unloading is completed, the control system compresses the head, and the liquid collecting plate is closed, to prepare for the next feeding operation.

[0036] In summary, the present application can effectively prevent the sludge from blocking the compressed air pipeline, and provide a pressure relief channel and fault indication when the valve fails, by setting the back flushing check valve 11 and the T-shaped emptying pipe with the back flushing emptying valve 9 in the back flushing pipeline; by setting the online turbidity meter 16 on the pressing water backflow pipeline and the water tank backflow valve 67 and the external discharge valve 62 controlled by the online turbidity meter 16, when the water quality (turbidity > 1 NTU) is detected to be abnormal, the sludge-containing pressing water is automatically discharged to the pit 18, avoiding the vicious cycle of filter plate diaphragm damage caused by the recycling of the sludge-containing pressing water, eliminating the hidden danger of the vicious cycle of compressed air pipeline blockage and filter plate diaphragm damage in the prior art, the control process is clear, the degree of automation is high, and the reliability and production efficiency of the equipment operation are significantly improved.

[0037] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Improved diaphragm plate and frame filter press automation control method, characterized in that: The steps include: S1. After the machine head is pressed, the feed valve (1) and the first control valve (3) of the water supply pipe (15) of the squeeze water tank (20) are opened, and the second control valve (4) is adjusted according to the liquid level of the water tank (20); the feed pump (2) is manually started, and when the feed pressure reaches the set value, the feed pump (2) automatically stops and closes the feed valve (1) and the first control valve (3); S2, close the squeeze water return valve (6), start the squeeze water pump and open the squeeze pump outlet check valve (5), use the squeeze pump (7), after squeezing is completed, stop the squeeze water pump and close the squeeze pump outlet check valve (5), open the squeeze water return valve (6), and measure and control the water tank return valve (61) and the external discharge valve (62) according to the online turbidity meter (16); S3, open the sludge return valve (8), close the backflush emptying valve (9), open the backflush pneumatic valve (10), and the backflush check valve (11) automatically opens; after the backflush is completed, close the backflush pneumatic valve (10), the backflush check valve (11) automatically closes, and open the backflush emptying valve (9); S4: The machine head is pre-loosened, the liquid collecting plate is opened, and the machine head is released to wait for unloading; manual intervention starts the unloading procedure, and after unloading is completed, the machine head is pressed and the liquid collecting plate is closed.

2. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The feed pump (2) and the squeeze pump (7) are both variable frequency pumps.

3. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The water supply pipe (15) of the water tank (20) is jointly controlled by the first control valve (3) and the second control valve (4) during the water supply process of the water tank (20), wherein the water supply pipe (15) is plugged into the top of one side of the outer wall of the water tank (20), the first control valve (3) is installed on the side away from the water supply hole of the water tank (20) and is interlocked with the feed valve (1) of the plate and frame machine, and the second control valve (4) is installed on the side close to the water supply hole of the water tank (20) and is controlled to be switched by a radar level meter arranged on the top of the outer cavity of the water tank (20).

4. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The detection probe of the online turbidity meter (16) is fixed on the water inlet main of the squeeze water flow, and a turbidity sensor is provided on the detection probe, which is connected to the central processing unit of the control system (19) through a wireless communication module; the central processing unit includes a data receiving module, a data analysis module and an alarm control module, the data analysis module sets the turbidity critical value to 1NTU, and the alarm control module is connected to the alarm light of the display screen of the control system (19).

5. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The squeeze water return valve (6) controls the inlet of the return pipeline. The return pipeline is a three-way pipeline, one outlet of which is controlled by the water tank return valve (61) and leads to the squeeze water tank (20), and the other outlet is controlled by the external discharge valve (62) and leads to the ditch (18); the switches of the water tank return valve (61) and the external discharge valve (62) are both measured and controlled by the online turbidity meter (16); when the turbidity of the return water is ≤1NTU, the external discharge valve (62) is closed and the water tank return valve (61) is opened; when the turbidity of the return water is greater than 1NTU, the water tank return valve (61) is closed and the external discharge valve (62) is opened, and an alarm signal is triggered at the same time.

6. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The back-blowing pneumatic valve (10) and the back-blowing one-way valve (11) are connected to the back-blowing end (12) of the mud supply pipeline through flanges in sequence, and the outlet direction of the back-blowing one-way valve (11) is toward the back-blowing end (12); one end of the back-blowing pneumatic valve (10) is connected to the compressed air pipeline network, and the other end of the back-blowing pneumatic valve (10) is connected to the inlet end of the back-blowing one-way valve (11); the back-blowing one-way valve (11) 11 and the back-blowing pneumatic valve (10) 10 are both used to prevent sludge from entering the air pipeline.

7. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The back-blowing emptying valve (9) controls the emptying pipe (13), and the emptying pipe (13) is connected between the back-blowing pneumatic valve (10) and the back-blowing one-way valve (11) to form a T-shaped pipeline, which is used to discharge sludge and issue an alarm when the back-blowing pneumatic valve (10) is damaged.

8. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The feed valve (1), the first control valve (3), the second control valve (4), the sludge return valve (8), the squeeze water return valve (6), the water tank return valve (61), the external discharge valve (62) and the back-blowing emptying valve (9) are all pneumatic valves, and all the pneumatic valves are equipped with cables and air sources.

9. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The specific method of the squeezing pump (7) in step S2 is: adjusting the frequency of the squeezing pump (7) according to real-time pressure feedback to maintain a constant squeezing pressure.

10. The improved automatic control method for diaphragm plate and frame filter press according to claim 1, characterized in that: The opening time and compressed air pressure value of the back-blowing pneumatic valve (10) in step S3 are preset by the control system (19). After the back-blowing is completed, the valve automatically closes and the back-blowing exhaust valve (9) is activated to release pressure.

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