Automatic air extractor of self-checking lithium bromide absorption unit

Abstract

An automatic air extractor of a self-checking lithium bromide absorption unit belongs to the technical field of lithium bromide absorption units with an automatic air extracting function, a control execution device of the automatic air extractor is composed of a vacuum air extracting pump and a vacuum electromagnetic stop valve, and a pressure detection device is mounted in an air storage chamber of the unit. And the main control board receives the internal pressure of the current unit detected by the pressure detection device, compares the pressure change trend with set parameters, and performs action indication on the sucking pump and the electromagnetic valve of the control output device. After the output device is started, the pressure of the unit is detected in real time, the action of the output device can be controlled through self-checking analysis, and an alarm is automatically given and a fault type is prompted when a fault occurs. The utility model can achieve the purpose that the unit automatically exhausts air to keep the vacuum degree in the unit.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium bromide absorption units with automatic air extraction functions, and in particular relates to a self-checking automatic air extraction device for lithium bromide absorption units. Background Art

[0002] The air in the ground lithium bromide absorption unit not only reduces the working capacity of the unit, but also greatly affects the service life. At present, the vacuum degree of lithium bromide absorption units on the market is mainly divided into two categories, one is the manual exhaust method combining a vacuum pump and a vacuum diaphragm valve (manual valve); the other is the automatic exhaust method using silver palladium tube heating.

[0003] Figure 3 This is a manual air extraction method, which means that the operator checks the vacuum degree of the vacuum pressure gauge and performs related air extraction operations. Note that the vacuum pump and the corresponding air extraction manual valve must be switched on and off in strict accordance with the operating procedures. Randomly reversing the order of switching may cause air leakage in the unit and damage the vacuum degree. Advantages of this method: obvious air extraction effect and short air extraction time. Disadvantages: waste of man-hours and complicated operation.

[0004] Another method is to heat the silver palladium tube to automatically exhaust, which is to heat the silver palladium tube to about 300℃ by external heating. At this time, the silver palladium tube has the ability to automatically exhaust the non-condensable gas in the gas storage chamber. Advantages: Automatic exhaust does not require manual operation. Disadvantages: The exhaust effect is not significant. How to make the exhaust system of the lithium bromide unit save manpower and working hours while having a better exhaust effect has become a current topic. Summary of the invention

[0005] In order to solve the above-mentioned problems, the utility model proposes: a self-checking lithium bromide absorption unit automatic exhaust device, including: a main control board, a pressure detection device, a control execution device, and an abnormal analysis execution device, and the main control board is connected to the pressure detection device, the control execution device, and the abnormal analysis execution device.

[0006] Furthermore, the main control board is a programmable controller PLC, and the programmable controller PLC is connected to the control mode switching device.

[0007] Furthermore, the pressure detection device is a pressure transmitter.

[0008] Furthermore, the control execution device is composed of a vacuum pump and a vacuum electromagnetic stop valve.

[0009] Furthermore, when an abnormality occurs in the unit or the air extraction system, the abnormality analysis execution device provides the user with an alarm prompt and the type of fault.

[0010] The beneficial effects of the utility model are as follows: the utility model replaces the manual inspection and judgment method with an intelligent PLC self-checking analysis and processing method, providing a timely and accurate analysis and judgment result, and the original lithium bromide absorption unit control system does not change. The main control board of the system adopts a logical control method instead of a direct judgment processing method, which can immediately handle emergencies and clearly judge specific problems to avoid false alarms or misreports. The control method of the system can be manually switched according to user needs to meet the requirements of the automatic exhaust system under special conditions. In engineering, if the vacuum exhaust pump or vacuum solenoid valve is out of stock, it can be quickly replaced with the original old exhaust method without any changes. This automatic exhaust system can meet the needs of different users for the exhaust function of the absorption unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The utility model is a schematic diagram of the input and output device control circuit of the automatic air extraction device of the self-checking lithium bromide absorption unit.

[0012] Figure 2 The utility model is a self-checking control logic flow chart of the automatic air extraction device of the self-checking lithium bromide absorption unit.

[0013] Figure 3 Schematic diagram of the suction device for artificial suction method. DETAILED DESCRIPTION

[0014] In order to make the technical means and objectives of the utility model easy to understand, the utility model is further described below in combination with a specific implementation method. A self-checking lithium bromide absorption unit automatic air extraction device includes: a main control board, a pressure detection device, a control execution device, and an abnormal analysis execution device; it is characterized in that the main control board is composed of a programmable controller PLC and a control mode switching device. The PLC internally writes processing programs such as self-checking pressure analysis and fault judgment to control the entire system to run accurately, effectively and quickly.

[0015] The pressure detection device is an absolute pressure transmitter, which has the characteristics of strong anti-interference ability.

[0016] The control execution device is composed of a vacuum air pump and a vacuum electromagnetic stop valve.

[0017] When an abnormality occurs in the unit or the exhaust system, the abnormality analysis execution device provides the user with an alarm prompt and the type of fault.

[0018] Among them, the vacuum electromagnetic stop valve is used in number of two to perform double shutoff and ensure the sealing reliability of the automatic air extraction device.

[0019] The self-checking control logic is a logic control method obtained based on the experience accumulated from long-term tests.

[0020] like Figure 1 As shown, the utility model performs action combinations according to the switching of the control mode, and the specific combination table is as follows:

[0021]

[0022] When the control mode is switched to manual, the start and stop of the vacuum pump and the switch of the solenoid valve of the vacuum system have nothing to do with the operation / stop of the absorption unit and the pressure of the air storage chamber.

[0023] When the control mode is switched to automatic, the main control panel receives the pressure detection device to detect the internal pressure of the current unit, and according to the trend of pressure change and the comparison with the set parameters, it gives the action instructions to the vacuum pump and solenoid valve of the control output device. When the output device is started, the unit pressure is constantly detected. Through self-checking analysis, the output device action can be controlled, and an automatic alarm and fault type can be prompted when a fault occurs. The purpose of automatically exhausting the unit to maintain the internal vacuum of the unit has been achieved.

[0024] like Figure 2 As shown in the self-checking control logic flow chart, when the pressure in the air storage chamber is higher than the starting pressure (ap-st), the vacuum pump starts to operate. After one minute, the current pressure value (P1) of the air storage chamber is recorded and the vacuum solenoid valves 1 and 2 are opened.

[0025] After 1 second, determine whether the current air storage chamber pressure is less than P1+0.5Kpa (one-time verification);

[0026] If the judgment result is "YES", check whether the control valve opening time is less than the valve opening pumping time (ap-tim) (secondary verification);

[0027] If the judgment result is "YES", reset all the abnormalities of air extraction and judge whether the current pressure of the air storage chamber is less than P1+0.5Kpa (three times of verification);

[0028] If the judgment result is "YES", whether the current air storage chamber pressure is less than the pumping stop pressure (ap-sp) (four times verification);

[0029] If the judgment result is "YES", the pre-alarm times (n) are reset, the air storage chamber solenoid valve is closed, and the air pump stops after another 10 seconds.

[0030] When the first check is "NO", the vacuum device will give a leakage alarm, close the solenoid valve, and then the vacuum pump will stop after 10 seconds and prompt the user to indicate that he has agreed to the operation.

[0031] When the second check is "NO", determine whether the current air storage chamber pressure is less than the starting pressure ap-st (fifth check);

[0032] If the judgment result is "YES", whether the number of pre-alarms is 0 (six times verification);

[0033] If the judgment result is "YES", the electromagnetic valve of the air storage chamber is closed, and after another 30 minutes, the air pump stops and the automatic air extraction system restarts again.

[0034] When the sixth check is "NO", the insufficient pumping capacity alarm is sounded, the solenoid valve is closed, and after 20 minutes, the pump stops. Through the above six tests, the normal pumping of the unit and the accurate and immediate response to various emergencies can be achieved. Finally, the internal vacuum degree of the lithium bromide absorption unit is successfully ensured by using the calibration automatic pumping device.

[0035] When the five checks are "NO", the vacuum device will give a leakage alarm, close the solenoid valve, and then the vacuum pump will stop after 10 seconds and prompt the user to indicate that he has agreed to the operation.

[0036] The self-checking lithium bromide absorption unit automatic air extraction device of this embodiment is characterized in that the main control panel receives the pressure detection device to detect the current internal pressure of the unit, compares the pressure change trend and the set parameters, and then issues action instructions to the control execution device and the abnormal analysis execution device after six verification analyses. It can realize the normal full-automatic air extraction of the unit and the accurate and immediate response to various emergencies, ensuring the vacuum degree requirements of the unit.

[0037] The above is only a preferred specific implementation method of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and concept of the utility model within the technical scope disclosed by the utility model, which should be covered by the protection scope of the utility model.

Claims

1. A self-checking lithium bromide absorption unit automatic air extraction device, characterized in that: include: A main control panel, a pressure detection device, a control execution device, and an abnormal analysis execution device. The main control panel is connected to the pressure detection device, the control execution device, and the abnormal analysis execution device.

2. The self-checking lithium bromide absorption unit automatic air extraction device as claimed in claim 1, characterized in that: The main control board is a programmable controller PLC, and the programmable controller PLC is connected to the control mode switching device.

3. The self-checking lithium bromide absorption unit automatic air extraction device as claimed in claim 1, characterized in that: The pressure detection device is a pressure transmitter.

4. The self-checking lithium bromide absorption unit automatic air extraction device as claimed in claim 1, characterized in that: The control execution device is composed of a vacuum air pump and a vacuum electromagnetic stop valve.

5. The self-checking lithium bromide absorption unit automatic air extraction device as claimed in claim 1, characterized in that: When an abnormality occurs in the unit or the exhaust system, the abnormality analysis execution device provides the user with an alarm prompt and the type of fault.

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