A method for automatic calibration and condition monitoring of a cooling water flow control valve

Abstract

The application discloses a kind of cooling water flow control valve automatic calibration and state monitoring method, belongs to proportional valve calibration technical field.The application of a kind of cooling water flow control valve automatic calibration and state monitoring method, switch control valve opens, PLC system sequentially outputs several current signals, proportional regulating valve is adjusted opening degree according to current signal, and water flow is sequentially changed, after water flow is stable, and PLC system records flow value by water flowmeter to obtain a flow value series, as proportional regulating valve's state detection data, and state detection data is compared with standard sample, if deviation exceeds set value, then interrupt calibration process and output alarm, if deviation is within allowable range, then adjust output current according to new state detection data.The application can be calibrated to proportional regulating valve one key, without manual detection and calibration, solve the problem that existing manual calibration needs to spend a lot of manpower and time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of proportional valve calibration, in particular to a method for automatic calibration and state monitoring of a cooling water flow control valve. BACKGROUND

[0002] Industrial production lines use a large amount of cooling water to rapidly cool equipment or workpieces. The size of the cooling water flow is crucial. In terms of cooling equipment, too small a flow will cause the equipment to overheat, leading to equipment failure or damage; too large a flow will increase the load on the water supply system, waste energy, and for direct spray cooling methods, it is not easy to control the direction of the spray, affecting the on-site environment. In terms of production workpieces, inaccurate water flow control has a greater impact. Different cooling intensities will result in different product organization properties, causing the product quality to be substandard.

[0003] In order to control the cooling water flow, a proportional regulating valve and a water flow meter need to be configured on the production line and periodically calibrated, but current cooling water flow calibration is generally manual, the process is relatively cumbersome, a large amount of manpower and time is required, and the efficiency is low. The flow characteristics of the control valve will change during production and use, and if there is no calibration and correction for a long time, the flow will not be accurate, causing equipment failure or product quality problems. SUMMARY

[0004] The purpose of the present application is to provide a method for automatic calibration and state monitoring of a cooling water flow control valve, which can achieve one-key automatic calibration of water flow during production line equipment maintenance, and detect whether the control valve state is abnormal during calibration, thereby solving the problems raised in the background art.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A method for automatic calibration and state monitoring of a cooling water flow control valve, comprising a water flow regulating system, the water flow regulating system comprising a proportional regulating valve, a water flow meter, an on-off control valve, and a PLC system, the automatic calibration and state monitoring being as follows: after the on-off control valve is opened, the PLC system outputs a plurality of current signals in turn, the proportional regulating valve adjusts the opening degree according to the current signals to cause the water flow to change in turn, after the water flow stabilizes, the PLC system records the flow value through the water flow meter to obtain a flow value sequence, which is used as state detection data of the proportional regulating valve, and the state detection data is compared with a standard sample, if the deviation in the comparison result exceeds a set value, the calibration process is interrupted, and an alarm is output to remind the maintenance personnel to check and replace; if the deviation is within the allowable range, the output current is adjusted according to the new state detection data and a calculation formula.

[0007] Preferably, the PLC system sends current signals to the proportional regulating valve, and the current values form an arithmetic sequence with a difference from 0 to maximum.

[0008] Preferably, the PLC system judges the water flow stability by calculating the difference between the values in two adjacent scanning periods, and when the difference is less than a certain set value and lasts for a certain time, it is determined that the water flow has been in a stable state.

[0009] Preferably, the current signal output by the PLC system corresponds to the opening degree of the proportional regulating valve of 0-100%.

[0010] Preferably, the water flow meter is connected to the PLC system and feeds back the current signal, and the current signal corresponds to the detection interval of the water flow meter from zero to the nominal maximum flow.

[0011] Preferably, after the proportional regulating valve is in a normal state, the PLC system calculates the required output current signal of the proportional regulating valve according to the production target water flow by using the slope of the broken line.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] 1. The present application outputs current signals in order from small to large by the PLC system, the proportional regulating valve adjusts the opening degree according to the current signal, and after the water flow changes and stabilizes, the flow value is recorded and a flow feedback table is formed, so that one-key calibration of the proportional regulating valve is realized, manual detection and manual calibration are not required, the operation is simple, and the production automation degree is effectively improved.

[0014] 2. After the calibration process is completed, the PLC system automatically analyzes and compares the flow feedback table to judge the state of the proportional regulating valve, automatically reminds the maintenance personnel to replace and process in time when the proportional regulating valve is determined to be abnormal, and when the proportional regulating valve is determined to be in a normal range, the current and water flow feedback data obtained during the calibration process are used, the PLC system calculates the required output current signal of the proportional regulating valve according to the production target water flow by using the slope of the broken line, so as to realize the purpose of accurate flow control.

[0015] 3. The present application corrects the flow deviation caused by the change of the characteristics of the proportional regulating valve in time, prevents potential equipment damage and energy loss, and avoids the occurrence of quality problems such as inconsistent product characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a current output and water flow feedback corresponding table of the present application;

[0017] Figure 2 is a schematic diagram of the normal sample state characteristics of the regulating valve of the present application;

[0018] Figure 3 Schematic diagram of abnormal state characteristics of the control valve of the present invention Figure 1 ;

[0019] Figure 4 Schematic diagram of abnormal state characteristics of the control valve of the present invention Figure 2 ;

[0020] Figure 5 Schematic diagram of abnormal state characteristics of the control valve of the present invention Figure 3 . DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] In order to solve the problem that the existing manual calibration of cooling water flow is cumbersome, requires a lot of manpower and time, and is inefficient, this embodiment provides the following technical solutions:

[0023] A method for automatic calibration and status monitoring of a cooling water flow control valve includes a water flow regulation system, which includes a proportional control valve, a water flow meter, a switch control valve and a PLC system. The proportional control valve can automatically adjust the valve opening according to changes in the current signal to achieve the required water flow; the water flow meter is used to detect the water flow size; the water flow switch valve is used to open or close the water flow, and when the switch valve is closed, the water flow is completely cut off.

[0024] Automatic calibration and status monitoring are as follows: After the switch control valve is opened, the PLC system outputs several current signals in sequence. The proportional control valve adjusts the opening degree according to the current signal to change the water flow in sequence. After the water flow stabilizes, the PLC system records the flow value through the water flow meter to obtain a flow value series as the status detection data of the proportional control valve, and compares the status detection data with the standard sample. If the deviation is found in the comparison result to exceed the set value, the calibration process is interrupted and an alarm is output to remind maintenance personnel to check and replace; if the deviation is within the allowable range, the output current is adjusted according to the calculation formula based on the new status detection data.

[0025] like Figure 1As shown, the current signal sent by the PLC to the proportional control valve is divided into a series of current values ​​from 0 to the maximum, containing n current values. In the PLC system, the output signal of the proportional control valve is set as an array of I[X] (I[0], I[1], I[2], I[3], I[4]...I

[15] , I

[16] ), and the 4-20mA current is divided into 17 levels in an arithmetic form. I[0] corresponds to the output of a 4mA current signal, I[1] corresponds to the output of a 5mA current signal, I[2] corresponds to the output of a 6mA current signal..., and so on. I

[15] corresponds to the output of a 19mA current signal, and I

[16] corresponds to the output of a 20mA current signal. The water flow meter feedback signal is set as an array of F[X]. F[0] to F

[16] are used to store the actual flow feedback value during the calibration process. After the calibration is completed, a data table corresponding to the current and flow is formed. The values ​​in the current data table are fixed, but the flow data changes with the actual collected and recorded results during each calibration process.

[0026] The basic conditions for automatic calibration of the water flow control regulating valve are: the upstream water pressure is normal, the water flow switch valve is in the open state, and the connection and control of the control regulating valve and flow meter by the PLC system are in normal state.

[0027] The specific automatic calibration process is as follows:

[0028] Step 1: After the operator triggers the automatic calibration button, all values ​​in the flow meter feedback signal F[X] array are cleared to zero.

[0029] Step 2: The PLC outputs I[0], a 4mA current signal, to the proportional valve. Wait for the flowmeter feedback signal to change. When the flowmeter feedback signal changes and remains relatively stable for more than 5 seconds, record the current flow value as F[0].

[0030] Step 3: After the PLC completes the storage of F[0], it outputs I[1], a 5mA current signal, to the proportional valve. Similarly, wait for the flow meter feedback signal to change. When the flow meter feedback signal changes and eventually remains relatively stable for more than 5 seconds, record the current flow value as F[1].

[0031] Step 4: After the PLC completes the storage of F[1], it outputs I[2], a 6mA current signal, to the proportional valve. Similarly, wait for the flow meter feedback signal to change. When the flow meter feedback signal changes and eventually remains relatively stable for more than 5 seconds, record the current flow value as F[2].

[0032] Step 5. In this way, the PLC gradually outputs I[3], I[4]....., to I

[16] , and records the flow value F[3], F[4]....., to F

[16] corresponding to each level of current.

[0033] Step six, until the F

[16] record storage is complete, the data sampling process ends.

[0034] The PLC system determines the water flow stability as follows: calculate the difference between the values of the adjacent two scanning periods, when the difference is less than a certain set value V0 and lasts for a certain time, it is determined that the water flow has been in a stable state, and the size of V0 is determined by the debugging result or experience.

[0035] The current signal output by the PLC system corresponds to the opening degree of the proportional regulating valve 0-100%. The water flow meter is connected to the PLC system and feeds back the current signal, and the current signal corresponds to the detection interval of the water flow meter from zero to the nominal maximum flow.

[0036] When the flow calibration is completed, the PLC system forms a flow feedback table with the water flow value sequence and compares it with the standard sample. When the data deviates significantly from the standard sample, it is determined that the proportional regulating valve may have an abnormal state and personnel need to further check.

[0037] Figure 2 The normal sample state characteristic diagram of the proportional regulating valve is shown, and several common abnormal states are listed as follows:

[0038] The value of F[0] should be close to 0, if the deviation is too large, it is determined that the state of the valve is abnormal, such as Figure 3 Regardless of the output current size, the regulating valve is always in a fixed opening state;

[0039] At a certain stage, when the flow feedback suddenly increases sharply or decreases as the current increases, it is determined that the state of the valve is abnormal, such as Figure 4 As shown;

[0040] In the early stage of current growth, the water flow increases, but in the middle and late stages, the current continues to increase, but the flow does not increase significantly, it is determined that the state of the valve is abnormal, such as Figure 5 As shown;

[0041] When the value of F

[15] is significantly less than the theoretical flow, it is determined that the state of the valve is abnormal.

[0042] After determining that the state of the proportional regulating valve is normal, the current and water flow corresponding table is obtained, and the current signal required by the PLC system is calculated through the slope of the broken line according to the production target water flow value.

[0043] In the subsequent production process, the output current corresponding to the production demand flow F(F<F

[16] ) is:

[0044]

[0045] Where F is the production target flow;

[0046] F N is the value slightly greater than the production target flow F in the flow table formed after calibration;

[0047] F N-1 is the value slightly less than the production target flow F in the flow table formed after calibration;

[0048] I N is the current value corresponding to F N in the flow table formed after calibration;

[0049] I N-1 is the current value corresponding to I N-1 in the flow table formed after calibration;

[0050] If F is exactly equal to a value in the flow table, the corresponding current in the table is directly outputted.

[0051] In the subsequent production process, if the production requires a flow F greater than or equal to F

[16] flow, I

[16] is directly outputted, i.e. the maximum current level. However, in the equipment design selection, the flow range of the flow control valve should be greater than the production requirement, and the case of F>=F

[16] generally does not occur.

[0052] If there is no abnormal situation in the proportional regulating valve, it can be used for production control after calibration.

[0053] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0054] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for automatic calibration and status monitoring of a cooling water flow control valve, comprising a water flow regulation system, characterized in that: The water flow regulation system includes a proportional control valve, a water flow meter, a switch control valve and a PLC system. The automatic calibration and status monitoring are as follows: after the switch control valve is opened, the PLC system sequentially outputs a number of current signals in equal increments. The proportional control valve adjusts its opening according to the current signal to change the water flow. After the water flow stabilizes, the PLC system records the flow value through the water flow meter to obtain a flow value series as the status detection data of the proportional control valve, and compares the status detection data with the standard sample. If the deviation in the comparison result exceeds the set value, the calibration process is interrupted and an alarm is output to remind maintenance personnel to check and replace the valve. If the deviation is within the allowable range, the output current is adjusted according to the calculation formula based on the new status detection data. The current signal sent by the PLC system to the proportional control valve ranges from 0 to the maximum, forming a current value series with an arithmetic progression, including n current values. The method used by the PLC system to determine the stability of water flow is as follows: the difference between the values ​​of the water flow in two adjacent scanning cycles is calculated. When the difference is less than a set value and lasts for a certain period of time, it is determined that the water flow has reached a stable state.

2. The method for automatic calibration and status monitoring of a cooling water flow control valve according to claim 1, characterized in that: The current signal output by the PLC system corresponds to the opening degree of the proportional control valve from 0 to 100%.

3. The method for automatic calibration and status monitoring of a cooling water flow control valve according to claim 2, characterized in that: The water flow meter is connected to the PLC system and feeds back a current signal, which corresponds to the detection interval of the water flow meter from zero to the nominal maximum flow.

4. The method for automatic calibration and status monitoring of a cooling water flow control valve according to claim 3, characterized in that: After the proportional control valve is in a normal state, the PLC system calculates the required proportional control valve output current signal using the broken line slope according to the production target water flow.

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