A circulating water filtering system for PVC production

Abstract

The utility model belongs to PVC production equipment technical field, concretely relates to a kind of circulating water filtration system for PVC production.It includes circulating water cooling system, filter device, waste water collection pond, circulating pump, filter press and check valve.The utility model provides a kind of circulating water filtration system for PVC production, and the cooperation of circulating pump, filter press and check valve, the backwashing waste water in waste water collection pond is filtered and then transported to filter system recycling, with the effect of saving water resources.

Description

Technical Field

[0001] This utility model belongs to the technical field of PVC production equipment, specifically relating to a circulating water filtration system for PVC production. Background Technology

[0002] The circulating water system in PVC production is mainly used for temperature control during the polymerization reaction process, ensuring that the heat of reaction can be effectively removed and maintaining the stability of the reaction. The circulating water system generally consists of circulating water pumps, cooling towers, and filtration systems. During long-term operation, a large amount of solid impurities accumulate. While existing circulating water filtration systems can effectively remove impurities from the circulating water and prevent equipment clogging and wear, the following technical problems still exist: First, the filtered impurities contain a large amount of water, which is directly discharged into the wastewater treatment plant along with the impurities, resulting in a serious waste of water resources. Utility Model Content

[0003] This utility model provides a circulating water filtration system for PVC production. The technical solution is as follows: it includes a circulating water cooling system, a filtration device, and a wastewater collection tank. The circulating water return main pipe of the circulating water cooling system is connected to the inlet of the filtration device. The filter water outlet of the filtration device is connected to the circulating water cooling system. The backwash wastewater outlet of the filtration device is connected to the wastewater collection tank. This utility model also includes a circulating pump, a filter press, and a check valve. The wastewater collection tank is connected to the filter press through a connecting pipeline equipped with the circulating pump. The filter press is connected to the inlet of the filtration device. The check valve is located on the pipeline between the filter press and the filtration device.

[0004] Furthermore, this utility model also proposes a system including a PLC controller, a liquid level sensor, and a normally closed solenoid valve. The liquid level sensor is located in the sludge collection tank, and the normally closed solenoid valve is located on the pipeline between the filter press and the filtration device. The PLC controller is electrically connected to the motors of the liquid level sensor, the normally closed solenoid valve, and the circulating pump.

[0005] Furthermore, this utility model also proposes a system including a sewage treatment plant, a two-position three-way solenoid valve I, and a two-position three-way solenoid valve II; the inlet of the two-position three-way solenoid valve I is connected to the circulating water return main pipe and a normally closed solenoid valve via pipelines, the first outlet of the two-position three-way solenoid valve I is connected to the inlet of the filter device, and the second outlet of the two-position three-way solenoid valve I is connected to the circulating water cooling system; the inlet of the two-position three-way solenoid valve II is connected to the circulating pump via pipelines, the first outlet of the two-position three-way solenoid valve II is connected to the filter press via pipelines, and the second outlet of the two-position three-way solenoid valve II is connected to the sewage treatment plant via pipelines; a PLC controller is electrically connected to the two-position three-way solenoid valve I and the two-position three-way solenoid valve II respectively.

[0006] As can be seen from the above, the circulating water filtration system for PVC production provided by this utility model, through the cooperation of a circulating pump, a filter press and a check valve, filters the backwash wastewater in the wastewater collection tank and then sends it back to the filtration system for recycling, which has the effect of saving water resources. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0008] like Figure 1 The illustrated circulating water filtration system for PVC production includes a circulating water system 1, a filter device 2, and a wastewater collection tank 3. The circulating water return main pipe 4 of the circulating water system 1 is connected to the inlet of the filter device 2, the filter outlet of the filter device 2 is connected to the circulating water system 1, and the backwash wastewater outlet of the filter device 2 is connected to the wastewater collection tank 3.

[0009] This utility model also includes a circulating pump 5, a filter press 6, and a check valve 7. The wastewater collection tank 3 is connected to the filter press 6 through a connecting pipe on which the circulating pump 5 is installed. The filter press 6 is connected to the inlet of the filtration device 2. The check valve 7 is located on the pipe between the filter press 6 and the filtration device 2.

[0010] The circulating pump 5 is a power device used to increase the liquid pressure in the wastewater collection tank 3. It can be a centrifugal pump or a screw pump, and its head must match the working pressure of the filter press 6. The filter press 6 is a device that achieves solid-liquid separation through mechanical extrusion. It can be a plate and frame filter press 6 or a belt filter press 6, and the filter plate aperture can be set to 0.05 mm to trap impurity particles. The check valve 7 is a valve that prevents the media from flowing backwards. It can be a swing check valve or a lift check valve, and its installation direction must be consistent with the media flow direction.

[0011] Specifically, the backwash wastewater in the circulating water return main pipe 4 is purified by the filter device 2, and the filtered water enters the circulating water system 1 for reuse, while the backwash wastewater enters the wastewater collection tank 3 for collection. The wastewater containing impurities in the wastewater collection tank 3 is pressurized by the circulating pump 5 and then enters the filter press 6, where solid-liquid separation is completed at a pressure of 0.3-0.5 MPa. The separated filtered water is reinjected into the inlet pipe of the filter device 2 through the check valve 7, mixes with the circulating water return water, and then re-enters the filtration system for reuse. When the drainage pressure of the filter press 6 is lower than the system pressure, the check valve 7 automatically closes to prevent backflow of the filtered water. The solid impurities after filtration are collected and treated centrally, realizing the graded utilization of backwash wastewater resources.

[0012] Through the above technical solution, this utility model significantly reduces the water consumption per ton of PVC production. The combined use of the circulating pump 5 and the check valve 7 ensures stable operation of the system within a pressure fluctuation range of 3-5 bar, avoiding equipment failures caused by pressure changes.

[0013] The present invention further includes a PLC controller 8, a liquid level sensor 9, and a normally closed solenoid valve 10. The liquid level sensor 9 is located in the wastewater collection tank 3, and the normally closed solenoid valve 10 is located on the pipeline between the filter press 6 and the filter device 2. The PLC controller 8 is electrically connected to the liquid level sensor 9, the normally closed solenoid valve 10, and the motor of the circulating pump 5.

[0014] Among them, PLC controller 8 refers to a programmable logic controller, which can be implemented using an industrial-grade modular controller, used to receive sensor signals and control the actions of actuators. Liquid level sensor 9 is a device for detecting liquid height, which can be implemented using a float-type or ultrasonic sensor, used to monitor the real-time water level of wastewater collection tank 3. Normally closed solenoid valve 10 is a valve that remains closed in the absence of power, which can be implemented using a direct-acting solenoid valve, used to block pipeline flow when not in operation.

[0015] Specifically, when the level sensor 9 detects that the water level in the wastewater collection tank 3 has reached a preset threshold, the signal is transmitted to the PLC controller 8, indicating that the wastewater collection tank 3 is full of backwash wastewater. The PLC controller 8 simultaneously sends a start command to the motor of the circulating pump 5, and also sends start commands to the normally closed solenoid valve 10, the circulating pump 5, and the filter press 6, according to a preset program. The circulating pump 5 transports the impurity-containing liquid from the wastewater collection tank 3 to the filter press 6 for filtration. After the normally closed solenoid valve 10 opens, it allows the liquid processed by the filter press 6 to flow back to the filtration device 2 for further filtration. When the liquid level falls below the set value, the PLC controller 8 cuts off the power to the circulating pump 5 and the filter press 6 and closes the solenoid valve, forming a closed-loop control.

[0016] Through the above technical solution, this utility model realizes the automatic circulation treatment of water-containing impurities in the wastewater collection tank 3, effectively recovering and filtering water from the impurities, and solving the problem of water waste caused by direct discharge in the prior art. At the same time, the PLC control realizes the automated operation of the treatment process, reducing the need for manual intervention and improving the stability of system operation.

[0017] This utility model further proposes to include a sewage treatment plant 11, a two-position three-way solenoid valve I 12, and a two-position three-way solenoid valve II 13; the inlet of the two-position three-way solenoid valve I 12 is connected to the circulating water return main pipe 4 and the normally closed solenoid valve 10 through pipelines respectively, the first outlet of the two-position three-way solenoid valve I 12 is connected to the inlet of the filter device 2, and the second outlet of the two-position three-way solenoid valve I 12 is connected to the circulating water system 1; the inlet of the two-position three-way solenoid valve II 13 is connected to the circulating pump 5 through pipelines, the first outlet of the two-position three-way solenoid valve II 13 is connected to the filter press 6 through pipelines, and the second outlet of the two-position three-way solenoid valve II 13 is connected to the sewage treatment plant 11 through pipelines; a PLC controller 8 is electrically connected to the two-position three-way solenoid valve I 12 and the two-position three-way solenoid valve II 13 respectively.

[0018] Specifically, when maintenance or cleaning of the filter device 2 or wastewater collection tank 3 is required, a manual command is sent to the PLC controller 8 to control the two-position three-way solenoid valves I12 and II13 to switch circuits. Specifically, the inlet of the two-position three-way solenoid valve I12 is connected to the second outlet, and the inlet of the two-position three-way solenoid valve II13 is connected to the second outlet. At this time, the circulating water return main pipe 4 directly supplies water to the circulating water system 1. Short-term defiltration water supply will not damage the equipment and ensures the continuity of PVC production. After replacing the filter element in the filter device 2 and flushing and maintaining the filter device 2 and wastewater collection tank 3, a manual command is sent to the PLC controller 8 to control the circulating pump 5 to discharge the backwash wastewater in the wastewater collection tank 3 into the sewage treatment plant 11 for centralized collection and treatment.

Claims

1. A circulating water filtration system for PVC production, comprising a circulating water system (1), a filtration device (2), and a wastewater collection tank (3), wherein the circulating water return main pipe (4) of the circulating water system (1) is connected to the inlet of the filtration device (2), the filter outlet of the filtration device (2) is connected to the circulating water system (1), and the backwash wastewater outlet of the filtration device (2) is connected to the wastewater collection tank (3), characterized in that: It also includes a circulating pump (5), a filter press (6) and a check valve (7). The wastewater collection tank (3) is connected to the filter press (6) through a connecting pipe on which the circulating pump (5) is installed. The filter press (6) is connected to the inlet of the filter device (2). The check valve (7) is located on the pipe between the filter press (6) and the filter device (2).

2. The circulating water filtration system for PVC production as described in claim 1, characterized in that: It also includes a PLC controller (8), a liquid level sensor (9) and a normally closed solenoid valve (10). The liquid level sensor (9) is located in the wastewater collection tank (3), and the normally closed solenoid valve (10) is located on the pipeline between the filter press (6) and the filter device (2). The PLC controller (8) is electrically connected to the motors of the liquid level sensor (9), the normally closed solenoid valve (10), and the circulating pump (5).

3. The circulating water filtration system for PVC production as described in claim 2, characterized in that: It also includes a sewage treatment plant (11), a two-position three-way solenoid valve I (12), and a two-position three-way solenoid valve II (13); the inlet of the two-position three-way solenoid valve I (12) is connected to the circulating water return main pipe (4) and the normally closed solenoid valve (10) through pipelines respectively, the first outlet of the two-position three-way solenoid valve I (12) is connected to the inlet of the filter device (2), and the second outlet of the two-position three-way solenoid valve I (12) is connected to the circulating water system (1); the inlet of the two-position three-way solenoid valve II (13) is connected to the circulating pump (5) through pipelines, the first outlet of the two-position three-way solenoid valve II (13) is connected to the filter press (6) through pipelines, and the second outlet of the two-position three-way solenoid valve II (13) is connected to the sewage treatment plant (11) through pipelines; the PLC controller (8) is electrically connected to the two-position three-way solenoid valve I (12) and the two-position three-way solenoid valve II (13) respectively.

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