Control method and system for disc type deslagging centrifugal machine

Abstract

The invention discloses a control method applied to a disc deslagging type centrifugal machine, automation of the whole process of starting, operation, deslagging and shutdown is achieved through automatically-controlled motor and valve actions, and the invention further provides a control system of the disc deslagging type centrifugal machine applied to the method. The method has the advantages of reducing resource waste, improving working efficiency, being simple and convenient to operate and wide in application range.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifuge devices, and in particular to a control method and system applied to a disc-type slag discharge centrifuge. Background Art

[0002] Disc stack centrifuges are widely used in chemical, biopharmaceutical, food, environmental protection and other industries. They are mainly used to separate sediments, filter solutions, extract liquid active ingredients, etc. Compared with other types of centrifuges, disc stack centrifuges have many advantages such as simple operation, high separation efficiency and large processing capacity.

[0003] In a large number of engineering practices, since disc-type slag discharge centrifuges have different mechanical structures for different purposes and different process characteristics, they often need to adopt matching drive devices and control methods, which makes the traditional control method less adaptable and lacks universality between different models; and the operation often relies on manual experience, with a low degree of automation, resulting in material waste and safety hazards, and improving operating efficiency. Summary of the invention

[0004] In order to overcome the shortcomings of traditional control methods, the present invention provides a control method and system for use in a disc-type slag discharge centrifuge, which can improve operating efficiency, has a high degree of automation, is comprehensive in functions, is easy to operate, and has a wide range of applications.

[0005] The present application provides a control method for a disc-type slag discharge centrifuge, comprising the following steps:

[0006] Step 1: Initialize the system and determine whether there is a vibration sensor fault or a frequency converter fault; if so, an audible and visual alarm is issued and the centrifuge is prohibited from starting. The centrifuge can be started only after the fault is removed; if there is no fault, a start signal is allowed to be sent to the centrifuge;

[0007] Step 2: After the centrifuge receives the start signal, the main motor of the centrifuge is started, and the speed of the centrifuge is gradually increased to a first set value under the drive of the main motor;

[0008] Step 3: monitoring the rotation speed of the centrifuge in step 2, and when the rotation speed of the centrifuge reaches a first set value, opening the sealing valve to pre-seal the centrifuge; the first set value is 70% of the full speed of the motor;

[0009] Step 4: Continuously monitor the speed and operating current of the centrifuge until the speed of the centrifuge reaches a second set value; the second set value is the full speed of the motor;

[0010] Step 5: When the speed of the centrifuge reaches the second set value, the feed valve is opened and the material enters the centrifuge;

[0011] Step 6: Discharge slag according to the set slag discharge interval;

[0012] Step 7: After each slag discharge in step 6 is completed, the timing of the slag discharge interval is restarted and the process returns to step 6 until the reaction stops;

[0013] Step 8: After the centrifuge receives the stop signal, close the feed valve;

[0014] Step 9: After completing step 8, open the opening valve to discharge the remaining material in the centrifuge;

[0015] Step 10: After completing step 9, the centrifuge begins to decelerate until it comes to a complete stop.

[0016] Preferably, in step 1, the system initialization is specifically as follows: each time the PLC is powered on again, a power-on initialization program is called to clear the database data, the records of the counter and the timer in the PLC, and to reset the flag of the logic judgment.

[0017] Preferably, in step 2, the pressure of the operating water needs to be detected before starting the centrifuge. If the pressure of the operating water reaches 2 bar, the main motor of the centrifuge is started, otherwise the main motor of the centrifuge is not started;

[0018] Preferably, in step 6, slag removal comprises the following steps:

[0019] Step 61: First, open the opening valve for a period of time ranging from 0.5 seconds to 3 seconds;

[0020] Step 62: Open the sealing valve again, the time range is 2 seconds to 8 seconds).

[0021] Preferably, in step 10, the deceleration of the centrifuge is specifically that the main motor of the centrifuge is braked and decelerated under the control of a frequency converter.

[0022] Preferably, when the rotation speed of the centrifuge drops to near zero speed, the centrifuge exits the shutdown stage, and the centrifuge gradually stops completely under the action of inertia.

[0023] Preferably, the vibration of the centrifuge is monitored, and when the vibration result exceeds a threshold, an alarm is issued and the centrifuge is shut down;

[0024] The threshold is divided into a first vibration threshold and a second vibration threshold;

[0025] When the vibration exceeds the first vibration threshold and falls below the second vibration threshold, an audible and visual alarm will be given; if the duration exceeds 3 minutes, the machine will enter a deceleration stop;

[0026] When the vibration exceeds the second vibration threshold, an audible and visual alarm is given and the machine immediately decelerates and stops.

[0027] Preferably, when the rotation speed of the centrifuge cannot reach the first set value, an audible and visual alarm is given, and the centrifuge is decelerated and stopped immediately.

[0028] Preferably, when a failure of the main motor of the centrifuge is detected, an audible and visual alarm is given, and the centrifuge is decelerated and stopped immediately.

[0029] The present invention also provides a control system using any of the above control methods, including an HMI touch screen, a PLC controller, a frequency converter, and a valve island;

[0030] The PLC controller is connected to the frequency converter and the valve island via a PROFINET bus network;

[0031] The HMI touch screen is connected to the PLC controller via industrial Ethernet to display the centrifuge operating parameters and realize human-computer interaction. Since the bus network has a faster and more efficient access speed, the control of the main motor inverter and peripheral valves is more flexible and diverse.

[0032] The beneficial effects of the present invention are:

[0033] (1) The control method of the disc-type slag discharge centrifuge described in the present invention realizes the automation of the entire process of starting, running, slag discharge and shutdown through the automatically controlled motor and valve actions, reduces resource waste, improves operating efficiency, is easy to operate, and has a wide range of applications.

[0034] (2) The control system of the disc-type slag discharge centrifuge described in the present invention has strong versatility and scalability; the structured and modular control method has good maintainability when dealing with different application requirements; because the access speed of the bus network is faster and more efficient, the use and control of the main motor inverter and peripheral valves are more flexible, thereby meeting production requirements, reducing power consumption, and achieving energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a flow chart of the control method of the present invention;

[0036] Figure 2 It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0038] like Figure 1 As shown, a control method flow chart of the present application applied to a disc slag discharge centrifuge includes:

[0039] 1: The fault detection module detects the status of the equipment system. If the speed is zero and the system has no faults, the disc slag discharge centrifuge is allowed to start.

[0040] 2: The startup process is controlled by the startup function block. By calling the motor drive module, the inverter is issued a startup and frequency setting command. The centrifuge gradually increases the speed under the operation of the inverter. After reaching the set frequency, pre-seal and wait for a period of time to detect whether the speed tends to be stable. If the speed does not continue to rise for 5 consecutive seconds, it is determined that the speed increase process is over and the centrifuge enters the running state.

[0041] 3: In the running state, the operation function module takes over the control, making the centrifuge work in the waiting mode, production mode or cleaning mode. The specific functions are realized by calling the waiting function module, production function module or cleaning function module respectively. The operator can select the corresponding working mode, and the operation function module will call the relevant function module.

[0042] 4: When the operator completes the production task or cleaning task, he can issue a shutdown command, and then the control system exits the current working mode and switches from the running state to the shutdown process.

[0043] ]5: The shutdown process is controlled by the shutdown function module. By calling the motor drive module, the inverter is issued a stop command. The centrifuge gradually decelerates under the operation of the inverter. The deceleration time is determined by the inverter setting. During the deceleration process, if the speed is detected to be lower than 100RPM, the shutdown process is determined to be over, and the disc slag centrifuge waits for the operator's start command again.

[0044] 6. The fault detection function module continuously detects vibration, speed, and inverter operation. When the following conditions are detected, a fault alarm is issued.

[0045] Fault name Fault Definition Treatment measures Vibration level 1 alarm Vibration higher than 5mm / s If there is no improvement for 1 minute, stop the machine Vibration secondary alarm Vibration higher than 8mm / s If there is no improvement for 5 seconds, the system will stop. Too high speed Speed ​​above 10800RPM none Speed ​​too low Speed ​​below 6000RPM none Current is too high Current greater than 11A for 5s Immediate shutdown Inverter failure Inverter failure Immediate shutdown Valve island failure Valve island communication failure Immediate shutdown

[0046] 7. After the fault alarm occurs, the exception handling function block is called for judgment and processing. The processing methods are divided into three types: sound and light alarm only, sound and light alarm and delayed shutdown, sound and light alarm and immediate shutdown. Different faults are processed differently.

[0047] Embodiment 1

[0048] According to the foregoing, this embodiment specifically discloses a control method for a disc-type slag discharge centrifuge,

[0049] Step 1: System initialization, determine whether there is a vibration sensor fault or inverter fault; if so, an audible and visual alarm is issued, and the centrifuge is prohibited from starting. The centrifuge can be started only after the fault is removed; if there is no fault, it is allowed to send a start signal to the centrifuge; the system initialization is as follows: each time the PLC is powered on again, the power-on initialization program is called to clear the database data, counter and timer records in the PLC, and reset the flag bit of the logic judgment;

[0050] Step 2: After the centrifuge receives the start signal, the main motor of the centrifuge is started. Driven by the main motor, the speed of the centrifuge gradually increases to the first set value. Before starting the centrifuge, the pressure of the operating water needs to be detected. If the pressure of the operating water reaches 2 bar (bar is a pressure unit, 1 bar = 100 kilopascals (kPa), indicating that 100,000 Newtons of pressure are applied to 1 square meter), the main motor of the centrifuge is started, otherwise the main motor of the centrifuge is not started.

[0051] Step 3: monitoring the rotation speed of the centrifuge in step 2, and when the rotation speed of the centrifuge reaches a first set value, opening the sealing valve to pre-seal the centrifuge; the first set value is 70% of the full speed of the motor;

[0052] Step 4: Continuously monitor the speed and operating current of the centrifuge until the speed of the centrifuge reaches a second set value; the second set value is the full speed of the motor;

[0053] Step 5: When the speed of the centrifuge reaches the second set value, the feed valve is opened and the material enters the centrifuge;

[0054] Step 6: Deslagging according to the set deslagging interval; the deslagging steps include:

[0055] Step 61: First, open the opening valve for a period of time ranging from 0.5 seconds to 3 seconds;

[0056] Step 62: Open the sealing valve again, the time range is 2 seconds to 8 seconds);

[0057] Step 7: After each slag discharge in step 6 is completed, the timing of the slag discharge interval is restarted and the process returns to step 6 until the reaction stops;

[0058] Step 8: After the centrifuge receives the stop signal, close the feed valve;

[0059] Step 9: After completing step 8, open the opening valve to discharge the remaining material in the centrifuge;

[0060] Step 10: After completing step 9, the centrifuge begins to decelerate until it stops completely;

[0061] The deceleration of the centrifuge is specifically that the main motor of the centrifuge is braked and decelerated under the control of the frequency converter;

[0062] When the speed of the centrifuge drops to near zero speed, it exits the shutdown stage, and the centrifuge gradually stops completely under the action of inertia.

[0063] Embodiment 2

[0064] This embodiment is a preferred solution of the first embodiment, and performs fault monitoring on the centrifuge.

[0065] The vibration of the centrifuge is monitored, and when the vibration result exceeds the threshold, an alarm is issued and the machine is shut down;

[0066] The threshold is divided into a first vibration threshold and a second vibration threshold;

[0067] When the vibration exceeds the first vibration threshold and falls below the second vibration threshold, an audible and visual alarm will be given; if the duration exceeds 3 minutes, the machine will enter a deceleration stop;

[0068] When the vibration exceeds the second vibration threshold, an audible and visual alarm is given and the machine immediately decelerates and stops.

[0069] 8. The control method according to claim 1, characterized in that when the rotation speed of the centrifuge cannot reach the first set value, an audible and visual alarm is given and the centrifuge is decelerated and stopped immediately.

[0070] When a failure is detected in the centrifuge's main motor, an audible and visual alarm will sound and the machine will be decelerated and stopped immediately.

[0071] Embodiment 3

[0072] like Figure 2 As shown, a control system applied to a disc slag discharge centrifuge includes an HMI touch screen, a PLC controller, a frequency converter, a valve island, an intermediate relay, a main motor, a slag discharge device, various detection signals, various functional valve groups, etc. The PLC controller is connected to the frequency converter and the valve island through a PROFINET bus network, and the HMI touch screen is connected to the PLC controller through an industrial Ethernet to monitor the operation of the centrifuge and perform human-computer interaction.

[0073] The PLC programming language uses a mixed writing mode of the most common ladder diagram LAD and SCL languages. These two languages ​​have the widest support, strong readability, and are easy to design and maintain.

[0074] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

[0075] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A control method for a disc-type slag discharge centrifuge, characterized in that: The following steps are included: Step 1: Initialize the system and determine whether there is a vibration sensor fault or a frequency converter fault; if so, an audible and visual alarm is issued and the centrifuge is prohibited from starting. The centrifuge can be started only after the fault is removed; if there is no fault, a start signal is allowed to be sent to the centrifuge; Step 2: After the centrifuge receives the start signal, the main motor of the centrifuge is started, and the speed of the centrifuge is gradually increased to a first set value under the drive of the main motor; Step 3: monitoring the rotation speed of the centrifuge in step 2, and when the rotation speed of the centrifuge reaches a first set value, opening the sealing valve to pre-seal the centrifuge; the first set value is 70% of the full speed of the motor; Step 4: Continuously monitor the speed and operating current of the centrifuge until the speed of the centrifuge reaches a second set value; the second set value is the full speed of the motor; Step 5: When the speed of the centrifuge reaches the second set value, the feed valve is opened and the material enters the centrifuge; Step 6: Discharge slag according to the set slag discharge interval; Step 7: After each slag discharge in step 6 is completed, the timing of the slag discharge interval is restarted and the process returns to step 6 until the reaction stops; Step 8: After the centrifuge receives the stop signal, close the feed valve; Step 9: After completing step 8, open the opening valve to discharge the remaining material in the centrifuge; Step 10: After completing step 9, the centrifuge begins to decelerate until it comes to a complete stop.

2. The control method according to claim 1, characterized in that: In step 1, the system initialization is specifically as follows: each time the PLC is powered on again, the power-on initialization program is called to clear the database data, counter and timer records in the PLC, and reset the flag bit of the logic judgment.

3. The control method according to claim 1, characterized in that: In step 2, the pressure of the operating water needs to be detected before starting the centrifuge. If the pressure of the operating water reaches 2 bar, the main motor of the centrifuge is started. If not, the main motor of the centrifuge is started after the pressure reaches 2 bar.

4. The control method according to claim 1, characterized in that: In step 6, slag removal includes the following steps: Step 61: First, open the opening valve for a period of time ranging from 0.5 seconds to 3 seconds; Step 62: Open the sealing valve again, the time range is 2 seconds to 8 seconds).

5. The control method according to claim 1, characterized in that: In step 10, the deceleration of the centrifuge is specifically that the main motor of the centrifuge is braked and decelerated under the control of the frequency converter.

6. The control method according to claim 5, characterized in that: When the speed of the centrifuge drops to near zero speed, it exits the shutdown stage, and the centrifuge gradually stops completely under the action of inertia.

7. The control method according to claim 1, characterized in that: Monitor the vibration of the centrifuge, and when the vibration result exceeds the threshold, issue an alarm and shut down the machine; The threshold is divided into a first vibration threshold and a second vibration threshold; When the vibration exceeds the first vibration threshold and falls below the second vibration threshold, an audible and visual alarm will be given; if the duration exceeds 3 minutes, the machine will enter a deceleration stop; When the vibration exceeds the second vibration threshold, an audible and visual alarm is given and the machine immediately decelerates and stops.

8. The control method according to claim 1, characterized in that: When the speed of the centrifuge cannot reach the first set value, an audible and visual alarm is given, and the centrifuge is decelerated and stopped immediately.

9. The control method according to claim 1, characterized in that: When a failure is detected in the centrifuge's main motor, an audible and visual alarm will sound and the machine will be decelerated and stopped immediately.

10. A control system using the control method according to any one of claims 1 to 9, characterized in that: Including HMI touch screen, PLC controller, frequency converter, valve island; The PLC controller is connected to the frequency converter and the valve island via a PROFINET bus network; The HMI touch screen is connected to the PLC controller via industrial Ethernet to display the centrifuge operating parameters and realize human-computer interaction.

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