An integrated flushable intelligent liquid level transmitter

Abstract

The present invention provides an integrated flushable intelligent liquid level transmitter, which realizes the flushing and purging functions of the liquid level transmitter housing and process connection equipment through the solenoid valve integrated in the housing and the external automatic flushing and purging medium; combines the data collected by the pressure-variable ceramic sensor and the micro water flow switch to realize the intelligent blockage judgment and automatic exhaust functions of the liquid level transmitter; the present invention can not only meet the precise level measurement function, but also intelligently judge whether the current transmitter process connection is blocked, automatically start backwashing, and automatically exhaust, thereby greatly improving the accuracy of level detection; the overall structure is compact and the size is small, which greatly saves installation space and is suitable for sites with limited space; the instrument is highly intelligent and has a built-in blockage alarm output, which reduces system overhead and cost while reducing manual inspections, facilitates daily maintenance of the instrument, and has good stability and reliability.

Description

Technical Field

[0001] The present invention is applicable to the fields of chemical industry, fermentation, food processing and pharmaceutical industry. By designing an integrated flushable intelligent liquid level transmitter, functions such as nitrogen purge, process water backflushing, and intelligent blockage judgment are realized. On the basis of improving the integration of the instrument, the reliability of the instrument is increased, the frequency of system maintenance is reduced, the burden on the control system is alleviated, and costs are saved. Background Art

[0002] Traditional pressure-type liquid level transmitters are mostly used for level detection in the chemical, fermentation, food processing and pharmaceutical industries. The liquid level transmitter transmits signals to the control system, which is logically linked with the actuator to achieve automatic control of the production process. However, some measured objects are viscous, have poor fluidity, or have too high a solid content. Under slightly harsh environmental conditions, it is very easy to cause blockage at the process connection of the instrument interface. When a blockage occurs, it is first necessary to manually determine the location of the blockage, manually remove the process connection for cleaning, or configure the system with a separate solenoid valve and controller for backwashing, which greatly increases the workload and system overhead and reduces production efficiency. In addition, whenever the equipment is emptied, there is gas in the process connection, and the exhaust valve needs to be manually opened for exhaust, which increases the workload of manual inspections. The present invention realizes an integrated liquid level transmitter. The transmitter itself integrates the functions of automatic exhaust, intelligent blockage judgment, nitrogen backwashing and process water backwashing, which is of great significance in actual production. Summary of the Invention

[0003] The purpose of the present invention is to provide an integrated flushable intelligent liquid level transmitter, which, while meeting the normal level measurement function, can intelligently determine whether the current transmitter process connection is blocked, automatically start backwashing, and automatically exhaust, thereby improving the accuracy of level detection.

[0004] The present invention is achieved in this way:

[0005] A flushable, intelligent liquid level transmitter integrates a piezoelectric ceramic sensor, a backwash solenoid valve, a compressed air solenoid valve, an exhaust solenoid valve, and a display operation panel in a single housing. The transmitter is uniformly controlled by a single-chip microcomputer and outputs the measured liquid level and an alarm signal. The piezoelectric ceramic sensor is used for liquid pressure detection, the backwash solenoid valve is mounted on the outside of the housing, the compressed air solenoid valve and the exhaust solenoid valve are mounted on the inside of the housing, and the display operation panel is mounted on the top inner side of the housing. A blockage fault relay is also provided, which activates and outputs an alarm signal when a blockage occurs. The intelligent liquid level transmitter can be set to three backwash functions: using nitrogen, using process water, or using process water followed by nitrogen blow-drying.

[0006] 1. The selection of nitrogen specifically includes: opening the compressed air solenoid valve.

[0007] 2. The selected process water is specifically: Open the backwash solenoid valve.

[0008] 3. After using the selected process water, nitrogen is used for drying, specifically: Set the parameters in the panel: SpT1 is the time interval between two backwashes, SpT2 is the time for a single backwash, and SpT3 is the time for compressed nitrogen purging; the backwash time timer T1 of the instrument starts timing and accumulating. When T1 ≥ SpT1, start the backwash timer T2 to accumulate. When T2 < SpT2, open the backwash solenoid valve to backwash the inside of the cavity of the level transmitter and the process connection. When T2 ≥ SpT2, start the backwash timer T3 to accumulate. When T3 < SpT3, open the compressed air solenoid valve to purge and dry the inside of the cavity of the level transmitter and the process connection with nitrogen. When T3 ≥ SpT3, clear T1, T2, and T3, and the system automatically enters the next backwashing cycle.

[0009] 4. It has an intelligent blockage judgment function, specifically:

[0010] The set parameters are displayed on the operation panel and run automatically; when the entire level transmitter is backwashed, the pressure value Pt1 of the piezoelectric ceramic sensor is monitored in real time. Taking the backwash with process water as an example, set the supply pressure SpPt2 of the process water in the control panel, and calculate CaPt02 = 0.8 * SpPt2 at the same time. When the last second of the process water backwash ends, compare Pt1 with CaPt02. Since the pressure of the process backwash water is much higher than the upper limit of the material range set by the transmitter, when Pt1 > CaPt02, it can be judged that a blockage has occurred at the process connection. At this time, the output value of the transmitter is the upper limit of the range, and the blockage fault relay outputs an alarm signal.

[0011] 5. It has an automatic exhaust function, specifically:

[0012] The set parameters are displayed on the operation panel and run automatically; when the level gauge detects a sudden change in the pressure value Pt1 of the piezoelectric ceramic sensor when the equipment is in an empty tank or empty pipe state, the level transmitter automatically performs an exhaust operation, opens the exhaust solenoid valve, and at this time, the air in the cavity is discharged by the exhaust solenoid valve; after the air has been completely discharged, the exhaust solenoid valve is automatically closed after a 2-second delay, ending the automatic exhaust operation.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1. The process connection interface of this level transmitter is a DN50 flange interface, which is connected to the equipment or pipeline flange interface to contact the material. The transmitter uses a piezoelectric ceramic sensor to achieve the function of liquid level detection;

[0015] 2. The present invention adopts an integrated and highly integrated structural design, integrating the piezoelectric ceramic sensor, backwash solenoid valve, compressed air solenoid valve, and exhaust solenoid valve into a single housing. The system is uniformly controlled by a single-chip microcomputer and outputs the measured liquid level and alarm signals.

[0016] 3. The automatic backwashing time interval and the selection of backwashing medium can be set through the control panel of the liquid level transmitter to realize the backwashing of the liquid level sensor and cavity;

[0017] 4. The sensor automatically determines whether the process connection is blocked by the change in the pressure measurement value during backwashing. If blockage occurs, the instrument panel will prompt it, and the relay at the instrument output terminal will operate to output an alarm.

[0018] 5. The automatic exhaust time can be set through the control panel of the liquid level transmitter. When the equipment is empty or the pipe is empty, the exhaust operation will be automatically performed when liquid is refilled;

[0019] 6. The function of the present invention is to use a highly integrated structural design to integrate the exhaust solenoid valve, backwash actuator and liquid level transmitter into an integrated package. It can be installed in a small and limited space, saving space, making the site neat and beautiful, and reducing the amount of installation and maintenance work.

[0020] 7. The present invention replaces the traditional manual exhaust valve, backwash actuator and liquid level transmitter. It can choose compressed nitrogen or process water backwashing and automatic exhaust. At the same time, the control of the actuator is centralized in the single chip microcomputer in the liquid level transmitter, which no longer occupies the control point of the DCS system, saving system cost and reducing system overhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1a -b is a structural diagram of an integrated flushable intelligent liquid level transmitter;

[0022] Figure 2 This is the assembly outline drawing of an integrated flushable intelligent liquid level transmitter;

[0023] Figure 3 This is a flow chart for intelligent backwashing of an integrated flushable intelligent level transmitter;

[0024] Figure 4 This is a flow chart for intelligent blockage detection of an integrated flushable intelligent liquid level transmitter;

[0025] Figure 5 This is an automatic exhaust flow chart for an integrated flushable intelligent liquid level transmitter.

[0026] Among them, a-shell, b1-level gauge electrical wiring port, b2-solenoid valve wiring port, c-process connection port d-cavity, h-meter cover, e1-process water interface, e2-process water flushing port, f1-compressed nitrogen interface, f2-compressed nitrogen purge port, i-window, g1-shell exhaust port, g2-cavity exhaust port, j-compressed nitrogen solenoid valve maintenance port, k-exhaust solenoid valve maintenance port, S1-piezoelectric ceramic sensor, L1-piezoelectric ceramic sensor wiring, S2-micro water flow switch, L2-micro water flow switch wiring, V1-compressed nitrogen solenoid valve, L3-compressed nitrogen solenoid valve wiring, V2-process water backwash solenoid valve, V3-exhaust solenoid valve, L4-process water backwash solenoid valve wiring, L5-exhaust solenoid valve wiring, M1-display operation panel, L6-display panel cable, M2 contains the main circuit board of the single-chip microcomputer. DETAILED DESCRIPTION

[0027] The following is a further description of the novel integrated flushable intelligent liquid level transmitter of the present invention in conjunction with the accompanying drawings:

[0028] The compressed nitrogen solenoid valve, process water backwash solenoid valve and automatic exhaust solenoid valve compactly installed in the shell are controlled by a single-chip microcomputer, and the detection signals of the electro-ceramic sensor and the micro water flow switch are input into the single-chip microcomputer. The measured value of the transmitter is displayed locally using the display panel, and the parameters can also be set on the panel. While the transmitter outputs the liquid level signal normally, it is also provided with a blockage fault relay, which operates and outputs when blockage occurs; the single-chip microcomputer, the compressed nitrogen solenoid valve and the process water backwash solenoid valve can realize three backwashing functions of automatic nitrogen (or compressed air according to the characteristics of the measured medium), process water or nitrogen drying after process water in the instrument according to the settings; the single-chip microcomputer, the automatic exhaust solenoid valve and the micro water flow switch can realize the automatic exhaust function of the cavity and process connection in the instrument according to the settings; the single-chip microcomputer, the electro-ceramic sensor and the fault relay can realize the self-diagnosis of intelligent blockage of the process connection in the instrument, and the blockage fault relay will operate and output an alarm signal in the event of a fault;

[0029] The relevant technical features of the integrated flushable intelligent liquid level transmitter of the present invention are as follows:

[0030] 1. The compressed nitrogen backwash solenoid valve, process water backwash solenoid valve, piezoelectric ceramic sensor, single-chip microcomputer, display screen and other equipment are integrated into one housing. During use, only the process connection needs to be connected to the corresponding medium and electrical interface;

[0031] 2. This smart transmitter can be set to three backwash functions: using nitrogen, using process water, or using process water followed by nitrogen blow-drying;

[0032] 3. A φ8 solenoid valve is integrated in the housing and controlled by a single chip microcomputer to achieve backwashing or drying functions with compressed nitrogen (or compressed air according to the characteristics of the measured medium);

[0033] 4. A DN25 solenoid valve is integrated into the housing and can realize the backwash function of process water through single chip microcomputer control;

[0034] 5. A φ8 solenoid valve is integrated in the housing and controlled by a single chip microcomputer to realize the process connection automatic exhaust function;

[0035] 6. The backwash control, intelligent blockage control and exhaust control of this intelligent transmitter are all realized locally, without the need for external DCS system control signals;

[0036] 7. When it is determined that the process connection is blocked, the liquid level output signal is automatically output according to the full scale, and the alarm output relay is activated at the same time.

[0037] like Figure 1a The liquid level transmitter shown in Figure -b is enclosed in housing a. The connection between the housing and the device under test is through a DN50 raised-face flange at process connection port c. The housing's exterior includes a level gauge electrical connection port b1 for electrical wiring and a solenoid valve connection port b2 for solenoid valve V2. The housing also features a process water connection port e1 with a DN25 thread for external process water; a compressed nitrogen connection port f1 with a φ8 quick-connect plug for compressed nitrogen; and a housing exhaust port g1 with a φ8 quick-connect plug for exhausting to the atmosphere.

[0038] A cavity d is designed inside the shell. A piezoelectric ceramic sensor S1 is embedded in the top of the cavity for liquid pressure detection; a micro water flow switch S2 is embedded in the side of the cavity for fluid detection during exhaust; a process water flushing port e2 is embedded in the side of the cavity, with a diameter of DN25, for flushing the inside of the cavity with pressurized process water, cleaning and unblocking process connections; a compressed nitrogen purge port f2 is embedded in the side of the cavity, with a diameter of φ8, for purging the cavity with compressed nitrogen; a cavity exhaust port g2 is embedded in the side of the cavity, with a diameter of φ8, for exhausting the cavity.

[0039] The main circuit board M2, containing the microcontroller, is fixed inside the housing and connected to the piezoelectric ceramic sensor via the piezoelectric ceramic sensor wiring L1 and the micro water flow switch wiring L2, respectively. The process water backwash solenoid valve V2, mounted outside the housing and sized at DN25, is connected to the main circuit board M2 via the process water backwash solenoid valve wiring L4 and is controlled by M2. The compressed nitrogen solenoid valve V1, sized at φ8, is integrated into the housing and connected to the main circuit board M2 via the compressed nitrogen solenoid valve wiring L3 and is controlled by M2. The exhaust solenoid valve V3, sized at φ8, is integrated into the housing and connected to the main circuit board M2 via the exhaust solenoid valve wiring L3 and is controlled by M2.

[0040] The display and operation panel M1 is mounted on the inside of the housing's top and connected to the main circuit board M2 via the display and operation panel cable L6. It serves as the human-machine interface for the on-site display panel and instrument setting inputs. A cover h is mounted on the top of the housing, and the operation panel can be observed through the viewing window i.

[0041] A compressed nitrogen solenoid valve inspection port j and an exhaust solenoid valve inspection port k are provided on the side of the shell, which can be used to inspect and replace the built-in compressed nitrogen solenoid valve V1 and exhaust solenoid valve V3.

[0042] like Figure 2 As shown, the entire instrument has a compact structure and is easy to install. It can be used in a small space. The highly integrated instrument eliminates the need for external control signals, saving the entire system overhead and cost.

[0043] The basic functions of the liquid level transmitter can be configured in the control panel M1, which will not be described here. The following only describes the implementation process of the intelligent backwash function, intelligent blockage detection and automatic exhaust function.

[0044] Combine Figure 3 The intelligent backwashing flow chart illustrates the implementation process. The intelligent backwashing function allows you to select the backwashing method on the control panel M1: Method 1: Backwash with compressed nitrogen, opening the solenoid valve V1; Method 2: Backwash with process water, opening the solenoid valve V2; Method 3: Backwash with process water first, then purge with compressed nitrogen.

[0045] At the same time, set the time interval SpT1 between two backwashes and the time SpT2 for a single backwash in the panel. If mode three backwashing is used, the time SpT3 for compressed nitrogen purge also needs to be set.

[0046] The implementation process is described below taking Method 3 as an example. The same applies to Method 1 and Method 2. After setting the parameters in the panel for Method 3, the backwash time timer T1 of the instrument starts accumulating time. When T1 ≥ SpT1, the backwash timer T2 starts accumulating time. When T2 < SpT2, the solenoid valve V2 is opened to perform backwashing on the inside of the cavity of the liquid level transmitter and the process connection. When T2 ≥ SpT2, the backwash timer T3 starts accumulating time. When T3 < SpT3, the solenoid valve V1 is opened to perform nitrogen purging and drying on the inside of the cavity of the liquid level transmitter and the process connection. When T3 ≥ SpT3, T1, T2, and T3 are reset to zero, and the system automatically enters the next backwashing cycle.

[0047] Combined with Figure 4 The intelligent blockage judgment and washing flowchart is used to illustrate the implementation process. The intelligent blockage judgment function sets parameters in the control panel M1 and runs automatically. When the entire liquid level transmitter is undergoing backwashing and flushing, the pressure value Pt1 of the piezoelectric ceramic sensor is monitored in real time. Taking the example of using process water for backflushing, the pressure of the process water supply SpPt2 is set in the control panel, and at the same time CaPt02 = 0.8 * SpPt2 is calculated. When it comes to the last second of the process water backwashing, Pt1 is compared with CaPt02. Since the pressure of the process backwashing water is much higher than the upper limit of the material measurement range set by the transmitter, when Pt1 > CaPt02, it can be judged that a blockage has occurred at the process connection. At this time, the output value of the transmitter is the upper limit of the range, and at the same time, the relay for blockage alarm operates and outputs.

[0048] Combined with Figure 5 The automatic exhaust flowchart is used to illustrate the implementation process. The automatic exhaust function sets parameters in the control panel M1 and runs automatically. When the liquid level gauge detects a sudden change in pressure Pt1 when the equipment is in an empty tank or empty pipe state, the liquid level transmitter automatically performs an exhaust operation, opening the exhaust solenoid valve V3. At this time, the air in the cavity is discharged through V3. At this time, the micro water flow switch S2 is detected. When S2 operates and there is liquid flowing out from V3, since V3 is at the top of the entire liquid level transmitter cavity, it can be judged that the air in the cavity has been exhausted. After SK1 operates and delays for 2 seconds, the exhaust solenoid valve V3 is automatically closed to end the automatic exhaust operation.

[0049] The present invention provides a flushable intelligent liquid level transmitter with stable and reliable performance and compact structure. Through the solenoid valve integrated in the shell, the external automatic flushing and purging medium realizes the flushing and purging functions of the shell and process connection equipment of the liquid level transmitter. Combining the data collected by the pressure-variable ceramic sensor and the micro water flow switch, the intelligent blockage judgment and automatic exhaust functions of the liquid level transmitter are realized. The integrated flushable intelligent liquid level transmitter can not only meet the precise level measurement function, but also intelligently judge whether the current transmitter process connection is blocked, automatically start backwashing, and automatically exhaust, greatly improving the accuracy of level detection; the overall structure is compact and the size is small, which greatly saves installation space and is suitable for venues with limited space; the instrument is highly intelligent and has its own blockage alarm output, which reduces system overhead and cost while reducing manual inspections, facilitates daily maintenance of the instrument, and has good stability and reliability.

Claims

1. An integrated flushable intelligent liquid level transmitter, characterized in that: Integrate a piezoelectric ceramic sensor, a backwash solenoid valve, a compressed air solenoid valve, an exhaust solenoid valve and a display operation panel in a housing, and uniformly control them through a single-chip microcomputer, and output the measured liquid level and alarm signals; the piezoelectric ceramic sensor is used for liquid pressure detection, the backwash solenoid valve is installed outside the housing, the compressed air solenoid valve and the exhaust solenoid valve are installed inside the housing, and the display operation panel is installed inside the top of the housing; a blockage fault relay is also provided, which operates to output an alarm signal when a blockage occurs. The intelligent liquid level transmitter can set a backwash function: select process water and then use nitrogen to blow dry; The specific operation of selecting process water and then using nitrogen to blow dry is as follows: set parameters in the panel: SpT1 is the time interval between two backwashes, SpT2 is the time of a single backwash, and SpT3 is the time of compressed nitrogen purging; the backwash time timer T1 of the instrument starts timing and accumulating. When T1≥SpT1, the backwash timer T2 starts accumulating. When T2<SpT2, the backwash solenoid valve is opened to backwash the inside of the cavity of the liquid level transmitter and the process connection; when T2≥SpT2, the backwash timer T3 starts accumulating. When T3<SpT3, the compressed air solenoid valve is opened to purge and blow dry the inside of the cavity of the liquid level transmitter and the process connection with nitrogen. When T3≥SpT3, T1, T2, and T3 are cleared, and the system automatically enters the next backwashing cycle.

2. The integrated flushable intelligent liquid level transmitter according to claim 1, characterized in that: It has an automatic exhaust function, specifically as follows: Set parameters in the display operation panel and run automatically; when the liquid level gauge detects a sudden change in the pressure value Pt1 of the piezoelectric ceramic sensor when the equipment is in an empty tank or empty pipe state, the liquid level transmitter automatically performs an exhaust operation and opens the exhaust solenoid valve. At this time, the air in the cavity is discharged by the exhaust solenoid valve; after the air has been completely discharged, the exhaust solenoid valve is automatically closed after a 2-second delay, ending the automatic exhaust operation.

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