A chiller control system

Abstract

The application relates to a cold water machine control system for a cold water machine with a buffering structure, which comprises an initial state detection module, a parameter conversion module, a reset module, a constant liquid level control module, a constant temperature control module, a constant air pressure control module and a running state detection module; the initial state detection module is connected with the reset module; the parameter conversion module is connected with the constant liquid level control module, the constant temperature control module, the constant air pressure control module and the running state detection module respectively; the reset module is also connected with the running state detection module; and the constant liquid level control module, the constant temperature control module and the constant air pressure control module are all connected with the running state detection module. The application can make the cold water machine with the buffering structure applied to some water-using equipment with high vibration index requirements, and can improve the air pressure control precision.

Description

Technical Field

[0001] This invention relates to the field of chiller control technology, and more specifically to a chiller control system. Background Technology

[0002] A chiller is a device that provides low-temperature cooling water or chilled water through a refrigeration cycle. Its applications are very wide, and it can be used in almost any scenario requiring precise, stable, and continuous heat removal. A typical chiller consists of a water pump, water tank, piping, and water-using equipment to achieve circulation. This structure presents a problem where the water pump directly disturbs the water flow, causing water vibration.

[0003] In addition, most current water chillers only have temperature, liquid level, pressure alarm and flow rate regulation functions. In terms of constant pressure water supply control, the most commonly used method is variable frequency constant pressure water supply, which is to realize the circulating water supply through a closed-loop PID control system composed of a variable frequency drive and a water pressure sensor. The control accuracy of this solution is mostly ±0.1 bar, which is not high. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a chiller control system for use in chillers with buffer structures. This system features fully automatic constant air pressure, constant liquid level, constant temperature control, and equipment protection interlock control functions, with an air pressure control accuracy of ±0.01 bar.

[0005] This invention provides a chiller control system for a chiller with a buffer structure. The chiller includes a compressor, a condenser, a water tank, a water pump, a buffer tank, and a constant pressure control system connected in sequence. The chiller control system includes an initial state detection module, a parameter conversion module, a reset module, a constant liquid level control module, a constant temperature control module, a constant pressure control module, and an operating state detection module. The initial state detection module is connected to the reset module. The parameter conversion module is connected to the constant liquid level control module, the constant temperature control module, the constant pressure control module, and the operating state detection module, respectively. The reset module is also connected to the operating state detection module. The constant liquid level control module, the constant temperature control module, and the constant pressure control module are all connected to the operating state detection module.

[0006] Furthermore, the initial state detection module, the parameter conversion module, the reset module, the constant liquid level control module, the constant temperature control module, the constant pressure control module, and the operating state detection module are configured as follows:

[0007] The initial state detection module is used to detect the pressure of the compressor and whether an emergency stop signal is received. If the pressure of the compressor exceeds a preset value and / or an emergency stop signal is received, a reset signal is sent to the reset module.

[0008] The parameter conversion module is used to convert the results measured by the flow meter, level gauge, thermometer, and pressure gauge connected to the chiller control system into signals that can be recognized by the constant level control module, the constant temperature control module, the constant pressure control module, and the operating status detection module.

[0009] The reset module is used to receive a reset signal from the initial state detection module and / or the operating state detection module, so as to reset the compressor, condenser, constant pressure control system, solenoid valve, throttle valve and heater connected to the chiller control system;

[0010] The constant liquid level control module is used to detect the liquid level of the water tank and the buffer tank. When the liquid level of the buffer tank deviates from the set height, it controls the liquid level of the buffer tank to fluctuate near the preset liquid point and maintains a control accuracy of ±0.1mm. When the liquid level of the water tank deviates from the set liquid level range, the automatic water replenishment function is activated.

[0011] The constant temperature control module is used to detect the water temperature in the water tank and the buffer tank. When the water temperature in the water tank deviates from the set temperature, it controls the water temperature in the water tank to fluctuate around the preset temperature point and maintains a control accuracy of ±0.1℃. At the same time, it controls the water temperature difference between the buffer tank and the water tank to be maintained at 0.1℃.

[0012] The constant pressure control module is connected to the constant pressure control system and is used to detect the pressure in the buffer tank, control the preset pressure value to increase uniformly from 0 to the preset pressure threshold, and control the pressure in the buffer tank to be maintained at the pressure threshold.

[0013] The operating status detection module is used to detect the flow rate in the chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank, so as to indicate the operating status of the chiller control system.

[0014] Furthermore, the constant liquid level control module includes an automatic water replenishment unit. When the liquid level in the water tank is detected to be lower than the lower limit, the automatic water replenishment unit starts to automatically replenish water into the water tank until the liquid level in the water tank reaches its upper limit.

[0015] Furthermore, the automatic water replenishment unit includes an automatic water replenishment port connected to a water source, a throttle valve connected to the automatic water replenishment port, and a solenoid valve connected to the throttle valve.

[0016] Furthermore, the constant temperature control module includes a temperature detection unit. When the water temperature in the water tank is detected to be higher than the preset temperature value, a stop signal is sent to the compressor, and the compressor stops. When the water temperature in the water tank is detected to be lower than or equal to the preset temperature value, the compressor operates normally.

[0017] Furthermore, the operation status detection module includes:

[0018] The protection threshold setting unit is used to set the warning and alarm values ​​for the flow rate in the chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank.

[0019] The normal operation display unit is used to display the working status as normal when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are less than the warning value.

[0020] The warning display unit is used to display the working status as a warning state when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are greater than or equal to the warning value and less than the alarm value.

[0021] The alarm display unit is used to display the working status as alarm status when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are greater than or equal to the alarm value.

[0022] The chiller control system provided by this invention integrates fully automatic constant air pressure, constant liquid level, constant temperature control and equipment protection interlock control functions to realize automatic circulation of cooling water, effectively suppress the impact of water flow vibration, and enable chillers with buffer structures to be used in water-using equipment with high vibration index requirements; at the same time, the air pressure control accuracy of this invention can reach ±0.01 bar, which is an order of magnitude higher than the prior art. Attached Figure Description

[0023] Figure 1 This is a connection diagram of a chiller with a buffer structure.

[0024] Figure 2 This is a structural block diagram of the chiller control system according to the present invention.

[0025] Figure 3 This is a flowchart of the chiller control system according to the present invention. Detailed Implementation

[0026] To make the objectives, solutions, and advantages of this invention clearer, the specific structure and working principle of this invention will be described in more detail below with reference to the accompanying drawings. The embodiments described are for illustrative purposes only and are not intended to limit the scope of application of this invention.

[0027] The purpose of the following description is to provide the public with a clearer understanding of the present invention, while those skilled in the art will be able to understand the invention clearly even without the following detailed explanation.

[0028] This invention provides a chiller control system for a chiller with a buffer structure, such as... Figure 1 As shown, the chiller with a buffer structure provides a cooling cycle for the water-using equipment 70. It includes a compressor 10, a condenser 20, a water tank 30, a water pump 40, a buffer tank 50, and a constant pressure control system 60. The compressor 10 is connected to the condenser 20 and the water tank 30 through pipelines. The water tank 30 is also connected to the water pump 40, the buffer tank 50, and the water-using equipment 70 through pipelines. The buffer tank 50 is also connected to the water pump 40, the constant pressure control system 60, and the water-using equipment 70 through pipelines.

[0029] The compressor 10 is used for refrigeration and is connected to the water tank 30 via two pipelines: a high-pressure pipeline 11 and a low-pressure pipeline 12. The high-pressure pipeline 11 is equipped with a high-pressure protection switch 111 and a high-pressure gauge 112 to monitor whether the compressor 10 is operating normally, and also has a refrigerant injection port 113 for injecting refrigerant. The low-pressure pipeline 12 is equipped with a low-pressure gauge 121 and a first solenoid valve 122.

[0030] The condenser 20 is connected to the low-pressure pipeline 12, and the condenser 20 is also connected to the water tank 30 via a pipeline. A dryer 21 and a second solenoid valve 22 are installed on the pipeline connecting the condenser 20 and the water tank 30.

[0031] Water tank 30 has a manual water inlet 31, an automatic water inlet 32, a drain outlet 33, a water-using equipment inlet 34, a water pump inlet 35, and a bypass return outlet 36. The manual water inlet 31 is used for manual water supply. The automatic water inlet 32 ​​is connected to a common water source and is connected to the water tank 30 via a multi-level adjustable throttle valve 321 and a third solenoid valve 322 to prevent malfunctions caused by excessive water pressure. The drain outlet 33 is connected to the water tank 30 via a first drain valve 331. The water-using equipment inlet 34 is used to connect to a water source... For the hot water supply of the water-using equipment 70, a fourth solenoid valve 341 and a first flow meter 342 are installed on the pipeline connecting the water-using equipment inlet 34 and the water-using equipment 70; the water pump inlet 35 is connected to the water pump 40 to provide cooling water to the water pump 40, so that the cooling water in the water pump 40 flows into the buffer tank 50; the bypass return port 36 is connected to the return branch 361 to receive water returning from the buffer tank 50, and a first manual valve 362 is installed on the return branch 361 to control the flow rate of the return water.

[0032] In addition, the water tank 30 is equipped with a heat exchange copper pipe 371 and a heater 372. At the same time, the water tank 30 is equipped with a first level gauge 38 and a first thermometer 39 to monitor the water level and temperature in the water tank 30.

[0033] The water pump 40 is connected to the buffer tank 50 through a pipeline. On the pipeline connecting the water pump 40 and the buffer tank 50, there is a first pressure gauge 41, a second flow meter 42, a second manual valve 43 and a fifth solenoid valve 44. The aforementioned return branch 361 is located between the second manual valve 43 and the fifth solenoid valve 44.

[0034] The buffer tank 50 is equipped with a second level gauge 53, a second thermometer 54, a burst valve 55 and a constant pressure air inlet 561. The buffer tank 50 is also equipped with a water outlet 58 and a second pressure gauge 59 to monitor the pressure inside the buffer tank 50.

[0035] Continue to refer to Figure 1 The aforementioned constant pressure air inlet 561 is connected to the constant pressure control system 60, which in turn is connected to the compressed air inlet 61. An air inlet valve 62 is installed between the constant pressure control system 60 and the compressed air inlet 61. The water outlet 58 is connected to the water-using equipment 70 via a pipeline. A third manual valve 71 and a sixth solenoid valve 72 are installed on the pipeline connecting the water outlet 58 and the water-using equipment 70.

[0036] The compressor 10, condenser 20, constant pressure control system 60, high pressure protection switch 111, high pressure gauge 112, low pressure gauge 121, solenoid valves 122 / 22 / 322 / 341 / 44 / 72, throttle valve 321, flow meter 342 / 42, manual valve 362 / 43 / 71, level gauge 38 / 53, thermometer 39 / 54, pressure gauge 41 / 59, and heater 372 mentioned above are all connected to the chiller control system 80 of the present invention to realize constant pressure, constant level, and constant temperature control functions. Constant pressure refers to maintaining the internal pressure of the buffer tank 50 at ±0.01 bar; constant liquid level refers to the constant liquid level control function of the water tank 30 and the buffer tank 50, with a control accuracy of ±0.1 mm; constant temperature refers to controlling the water temperature of the water tank 30 and the buffer tank 50 within the range of 5~30℃, with a control accuracy of ±0.1℃, a temperature difference of 0.1℃ between the two containers, and a water temperature display and setting resolution of 0.1℃. The chiller control system 80 of this invention can also realize equipment protection functions, that is, it can provide early warning and alarm when the system malfunctions, and realize audible and visual alarms; at the same time, the chiller control system 80 of this invention can also realize automatic water replenishment function.

[0037] like Figure 2 As shown, the chiller control system 80 includes an initial state detection module 81, a parameter conversion module 82, a reset module 83, a constant liquid level control module 84, a constant temperature control module 85, a constant air pressure control module 86, and an operating state detection module 87. The initial state detection module 81 is connected to the reset module 83. The parameter conversion module 82 is connected to the constant liquid level control module 84, the constant temperature control module 85, the constant air pressure control module 86, and the operating state detection module 87. The reset module 83 is also connected to the operating state detection module 87. The constant liquid level control module 84, the constant temperature control module 85, and the constant air pressure control module 86 are all connected to the operating state detection module 87.

[0038] The functions and roles of each of the above modules are described in detail below.

[0039] The initial state detection module 81 is used to detect the pressure of the compressor 10 and whether an emergency stop signal has been received. If the pressure of the compressor 10 exceeds the preset value and / or an emergency stop signal is received, a reset signal is sent to the reset module 83 to reset the compressor 10, condenser 20, constant pressure control system 60, solenoid valves 122 / 22 / 322 / 341 / 44 / 72, throttle valve 321, and heater 372 connected to the chiller control system 80.

[0040] The pressure of the compressor 10 can be obtained through the high-pressure gauge 112 or through the status of the high-pressure protection switch 111. If the value of the high-pressure gauge 112 exceeds the preset value, or if the high-pressure protection switch 111 is in an abnormal state, a reset signal is issued. The emergency stop signal can be obtained through the status of the external emergency stop button. If the emergency stop button is detected to be pressed, a reset signal is issued.

[0041] The parameter conversion module 82 is used to convert the results measured by the flow meter 342 / 42, level gauge 38 / 53, thermometer 39 / 54, and pressure gauge 41 / 59 into signals that can be recognized by the constant level control module 84, constant temperature control module 85, constant air pressure control module 86, and operating status detection module 87.

[0042] The reset module 83 is used to receive reset signals from the initial state detection module 81 and / or the operating state detection module 87, so as to reset the compressor 10, condenser 20, constant pressure control system 60, solenoid valves 122 / 22 / 322 / 341 / 44 / 72, throttle valve 321, and heater 372 connected to the chiller control system 80.

[0043] The constant liquid level control module 84 is used to detect the liquid level of the water tank 30 and the buffer tank 50. When the liquid level of the buffer tank 50 deviates from the set height, it controls the liquid level of the buffer tank 50 to fluctuate near the preset liquid level point and maintains a control accuracy of ±0.1mm.

[0044] The constant liquid level control module 84 includes an automatic water replenishment unit 841. When the liquid level of the water tank 30 is detected to be lower than the lower limit, the automatic water replenishment unit 841 starts to automatically replenish water into the water tank 30 until the liquid level of the water tank 30 reaches its upper limit.

[0045] The automatic water replenishment unit 841 consists of the aforementioned automatic water replenishment port 32 connected to the water source, a multi-level adjustable throttle valve 321, and a third solenoid valve 322. When the liquid level in the water tank 30 is lower than the lower limit and water needs to be replenished, the throttle valve 321 and the solenoid valve 322 open to realize the automatic water replenishment function.

[0046] The constant temperature control module 85 is used to detect the water temperature in the water tank 30 and the buffer tank 50. When the water temperature in the water tank 30 and the buffer tank 50 deviates from the set temperature, it controls the water temperature in the water tank 30 and the buffer tank 50 to fluctuate around the preset temperature point, maintaining a control accuracy of ±0.1℃. It should be noted that the water temperature in the buffer tank 50 is not controlled independently; ideally, it is kept consistent with the water temperature in the water tank 30. In this invention, the water temperature difference between the water tank 30 and the buffer tank 50 is 0.1℃ and remains constant.

[0047] The constant temperature control module 85 includes a temperature detection unit 851. When the water temperature in the water tank 30 is detected to be higher than the preset temperature value, a stop signal is sent to the compressor 10, and the compressor 10 stops. When the water temperature in the water tank 30 is detected to be lower than or equal to the preset temperature value, the compressor 10 operates normally. After the compressor 10 stops, a timer can be started. After a preset time (e.g., 5 minutes), the compressor 10 can automatically start and continue working.

[0048] In this embodiment, both the constant liquid level control module 84 and the constant temperature control module 85 adopt PID controllers, and achieve closed-loop negative feedback constant liquid level and constant temperature control through the tuned PID parameters.

[0049] The constant pressure control module 86 is connected to the aforementioned constant pressure control system 60. It detects the pressure inside the buffer tank 50, controls the preset pressure value to increase uniformly from 0 to a preset pressure threshold (e.g., increasing by 0.025 bar every 2 seconds, reaching a pressure threshold of 0.8 bar after 64 seconds), and maintains the pressure in the buffer tank 50 at this pressure threshold. It should be noted that if the working pressure of the buffer tank 50 needs to be changed after reaching the pressure threshold, the pressure setting value can be manually changed.

[0050] The operation status detection module 87 is used to detect the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50, so as to indicate the working status of the entire control system 80.

[0051] More specifically, the operation status detection module 87 includes a protection threshold setting unit 871, a normal operation display unit 872, a warning display unit 873, and an alarm display unit 874.

[0052] The protection threshold setting unit 871 is used to set the warning and alarm values ​​for the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50.

[0053] The normal operation display unit 872 is used to display the working status as normal when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50 are less than the warning value. The normal status can be displayed as a solid green light.

[0054] The warning display unit 873 is used to display the working status as a warning state when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50 are greater than or equal to the warning value and less than the alarm value. The warning state can be displayed as a yellow light and a flashing buzzer.

[0055] The alarm display unit 874 is used to display the working status as alarm status when the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50 are greater than or equal to the alarm value. The alarm status can be displayed as a red light and a flashing buzzer.

[0056] like Figure 3 As shown, the control steps of the chiller control system 80 of the present invention can be referred to as follows:

[0057] Step S1: If the start button is pressed, proceed to step S2; if the stop button is pressed, a reset signal is sent to the reset module 83, resetting the compressor 10, condenser 20, constant pressure control system 60, solenoid valves 122 / 22 / 322 / 341 / 44 / 72, throttle valve 321, and heater 372 connected to the chiller control system 80.

[0058] In step S2, the initial state detection module 81 detects the pressure of the compressor 10 and whether an emergency stop signal has been received. If the pressure of the compressor 10 exceeds the preset value and / or an emergency stop signal is received, a reset signal is sent to the reset module 83 to reset all devices connected to the chiller control system 80; otherwise, proceed to step S3.

[0059] In step S3, the compressor 10 and condenser 20 are started, the constant liquid level control module 84 detects the liquid level in the water tank 30 and the buffer tank 50, and at the same time the constant temperature control module 85 detects the water temperature in the water tank 30 and the buffer tank 50.

[0060] Step S4: When the water level in tank 30 is detected to be below the lower limit, the throttle valve 321 and the third solenoid valve 322 are opened. When the water level in tank 30 reaches the upper limit, the throttle valve 321 and the third solenoid valve 322 are closed. When the difference between the actual water temperature in tank 30 and the preset temperature is detected to be greater than 5, the soft switch of compressor 10 is disconnected, compressor 10 stops, and the timer is started. After 5 minutes, compressor 10 is enabled normally. When the difference between the actual water temperature in tank 30 and the preset temperature is detected to be less than or equal to 0, the soft switch of compressor 10 is closed, and compressor 10 works normally.

[0061] Step S5: When the liquid level and water temperature of the water tank 30 are normal, open the valves related to the self-circulating water. When the water level is abnormal, activate the automatic water replenishment function. The constant liquid level control module 84 controls the liquid level of the buffer tank 50 to fluctuate near the preset point. The constant temperature control module 85 controls the water temperature of the water tank 30 and the buffer tank 50 to fluctuate near the preset temperature.

[0062] Step S6: When the liquid level and water temperature of the water tank 30 and the buffer tank 50 meet the working conditions (i.e. fluctuate within the preset liquid level range and preset temperature range), open the circulation valve on the water-using equipment 70.

[0063] In step S7, when the water temperature difference, constant liquid level control deviation, and constant temperature control deviation between the water tank 30 and the buffer tank 50 are less than the preset values, the constant air pressure control module 86 controls the preset air pressure value to increase by 0.025 bar every 2 seconds, reaching 0.8 bar after 64 seconds, and controls the air pressure of the buffer tank 50 to be maintained at 0.8 bar.

[0064] In step S8, the operating status detection module 87 detects the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50. When the absolute values ​​of the flow rate in the chiller pipeline, the water temperature difference between the water tank 30 and the buffer tank 50, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank 50 are less than the warning value, the operating status is displayed as normal, and the equipment is constantly lit with a green light.

[0065] The chiller control system 80 of the present invention has the following beneficial effects:

[0066] (1) This invention can not only be applied to equipment that requires cooling, but also meet the stability requirements of various equipment in the high-frequency band;

[0067] (2) The present invention is a cooling water circulation control system based on PLC hardware system, which coordinates the control of constant liquid level, constant temperature and constant air pressure. It can significantly reduce the fluctuation of water flow rate and make the equipment more stable in the high frequency range.

[0068] (3) Compared with a single-chip microcomputer system, the present invention has the advantages of low cost, short development cycle, more stability, more convenient maintenance, rich industrial communication interface and powerful human-computer interaction function;

[0069] (4) Compared with the existing constant pressure closed-loop PID control system of frequency converter, the constant air pressure control accuracy of the present invention is far better than 0.1 bar;

[0070] (5) This invention has the constant temperature control and temperature, liquid level and pressure alarm functions of ordinary water chiller, as well as the equipment protection interface design and automatic water replenishment design, and also has a special system normal operation condition design to ensure that the normal operation status of the system is clear at a glance.

[0071] (6) A circulating water control method with a combination of constant air pressure and constant liquid level, which keeps the dynamic water constant pressure vessel at a constant pressure (±0.01 bar).

[0072] (7) The gradual change of the set value by 0.025 bar every 2 seconds in the coordinated constant liquid level control design until it reaches 0.8 bar, takes 64 seconds. The system runs at this value and the set value can be manually changed after the end. This method can solve the one-button start-stop control. If this method is not added, the air pressure set value needs to be manually increased slowly until the liquid level is balanced and the system circulates normally. If the air pressure is increased too quickly, it is easy to cause the frequency converter to run out of control, thus preventing the system from operating normally.

[0073] (8) The compressor start-stop protection design and the temperature judgment compressor refrigeration overshoot shutdown design help to improve the compressor life.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A chiller control system for a chiller with a buffer structure, characterized in that, The water chiller comprises a compressor, a condenser, a water tank, a water pump, a buffer tank and a constant air pressure control system connected in sequence; the water chiller control system comprises an initial state detection module, a parameter conversion module, a reset module, a constant liquid level control module, a constant temperature control module, a constant air pressure control module and a running state detection module, the initial state detection module is connected with the reset module, the parameter conversion module is connected with the constant liquid level control module, the constant temperature control module, the constant air pressure control module and the running state detection module respectively, the reset module is further connected with the running state detection module, and the constant liquid level control module, the constant temperature control module and the constant air pressure control module are all connected with the running state detection module; The constant liquid level control module is used for detecting the liquid levels of the water tank and the buffer tank, when the liquid level of the buffer tank deviates from the set height, the liquid level of the buffer tank is controlled to fluctuate around the preset liquid level point with a control precision of ±0.1 mm, and when the liquid level of the water tank deviates from the set liquid level interval height, the automatic water supplement function is started; The constant temperature control module is used for detecting the water temperatures in the water tank and the buffer tank, when the water temperature of the water tank deviates from the set temperature, the water temperature of the water tank is controlled to fluctuate around the preset temperature point with a control precision of ±0.1℃, and the water temperature difference between the buffer tank and the water tank is controlled to be 0.1℃; The constant air pressure control module is connected with the constant air pressure control system and is used for detecting the air pressure in the buffer tank, controlling the preset air pressure value to uniformly increase from 0 to a preset air pressure threshold value, and controlling the air pressure of the buffer tank to be maintained at the air pressure threshold value; The running state detection module is used for detecting the flow rate in the water chiller pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation and the constant pressure control deviation of the buffer tank, so as to indicate the working state of the water chiller control system.

2. The chiller control system of claim 1, wherein, The initial state detection module, the parameter conversion module and the reset module are set as follows: The initial state detection module is used for detecting the pressure of the compressor and whether an emergency stop signal is received, and if the pressure of the compressor exceeds a preset value and / or an emergency stop signal is received, a reset signal is sent to the reset module; The parameter conversion module is used for converting the results measured by the flow meter, the liquid level gauge, the thermometer, the pressure gauge connected with the water chiller control system into signals recognizable by the constant liquid level control module, the constant temperature control module, the constant air pressure control module and the running state detection module; The reset module is used for receiving the reset signals from the initial state detection module and / or the running state detection module, so as to reset the compressor, the condenser, the constant air pressure control system, the electromagnetic valve, the throttle valve and the heater connected with the water chiller control system.

3. The chiller control system of claim 1, wherein, The constant liquid level control module comprises an automatic water supplement unit, when it is detected that the liquid level of the water tank is lower than the lower limit, the automatic water supplement unit starts to automatically supplement water into the water tank until the liquid level of the water tank reaches the upper limit.

4. The chiller control system of claim 3, wherein, The automatic water replenishing unit comprises an automatic water replenishing port connected with a water source, a throttle valve connected with the automatic water replenishing port, and an electromagnetic valve connected with the throttle valve.

5. The chiller control system of claim 1, wherein, The constant temperature control module comprises a temperature detection unit, which sends a stop signal to the compressor when detecting that the water temperature of the water tank is higher than a preset temperature value, and the compressor stops; and the compressor normally works when detecting that the water temperature of the water tank is lower than or equal to the preset temperature value.

6. The chiller control system of claim 1, wherein, The running state detection module comprises: a protection threshold setting unit for setting early warning values and alarm values of a flow rate in a water cooler pipeline, a water temperature difference between the water tank and the buffer tank, a constant liquid level control deviation, a constant temperature control deviation, and a constant pressure control deviation of the buffer tank; a normal running display unit for displaying a working state as a normal state when absolute values of the flow rate in the water cooler pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are less than the early warning values; an early warning display unit for displaying a working state as an early warning state when the absolute values of the flow rate in the water cooler pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are greater than or equal to the early warning values and less than the alarm values; and an alarm display unit for displaying a working state as an alarm state when the absolute values of the flow rate in the water cooler pipeline, the water temperature difference between the water tank and the buffer tank, the constant liquid level control deviation, the constant temperature control deviation, and the constant pressure control deviation of the buffer tank are greater than or equal to the alarm values.

Images