阅读说明：本技术 一种真空干燥箱自动控制系统及其控制方法 (Automatic control system and control method for vacuum drying oven ) 是由 郑陈业 朱靖华 苏超群 于 2020-05-15 设计创作，主要内容包括：本发明涉及一种真空干燥箱自动控制系统,包括依次管路连接的气体预处理组件、真空干燥箱、冷阱和真空泵,连接管路上均设置有自动控制阀门,还包括自动控制器,所述冷阱的外壁包裹有用于冷却冷阱的制冷片,所述冷阱底端连接有用于排出冷凝液的排液管,所述冷阱内设置有与所述控制器连接以监测冷阱内冷凝液体积的液位传感器,所述真空泵上设置有监测真空泵温度的温度传感器,所述的真空干燥箱内设置有温度、压力传感器,上述各传感器、阀门、真空泵、制冷片等均由自动控制器控制,所述的控制方法将操作规范步骤通过自动控制器按预定程序进行,解决现有真空干燥箱操作繁琐的缺陷,具有可连续自动运行的特点。(The invention relates to an automatic control system of a vacuum drying box, which comprises a gas pretreatment assembly, the vacuum drying box, a cold trap and a vacuum pump which are sequentially connected by pipelines, wherein automatic control valves are arranged on the connecting pipelines, an automatic controller is also included, a refrigerating sheet for cooling the cold trap is wrapped on the outer wall of the cold trap, a drain pipe for discharging condensate is connected at the bottom end of the cold trap, a liquid level sensor which is connected with the controller for monitoring the volume of the condensate in the cold trap is arranged in the cold trap, a temperature sensor for monitoring the temperature of the vacuum pump is arranged on the vacuum pump, temperature and pressure sensors are arranged in the vacuum drying box, all the sensors, the valves, the vacuum pump, the refrigerating sheet and the like are controlled by the automatic controller, the control method carries out standard operation steps by the automatic controller according to a preset program, and solves the defect that the existing vacuum drying box is complicated in operation, has the characteristic of continuous and automatic operation.)

1. The utility model provides a vacuum drying oven automatic control system which characterized in that: comprises a gas pretreatment component, a vacuum drying box, a cold trap and a vacuum pump which are connected by pipelines in sequence, and also comprises an automatic controller,

the outer wall of the cold trap is wrapped with a refrigerating sheet for cooling the cold trap, and the refrigerating sheet is controlled by the automatic controller;

a valve A for communicating or cutting off the pipeline is arranged on the pipeline between the vacuum drying box and the cold trap and is controlled by the automatic controller;

a valve B is arranged on a pipeline of the cold trap and the vacuum pump and is controlled by the automatic controller, the cold trap is communicated with the vacuum pump in a closed state, and the cold trap and the vacuum pump are both communicated with the external atmosphere in an open state;

the bottom end of the cold trap is connected with a liquid discharge pipe for discharging condensate, and a valve C is arranged on the liquid discharge pipe and is controlled by the automatic controller;

a liquid level sensor connected with the controller to monitor the volume of the condensate in the cold trap is arranged in the cold trap;

a valve D for pressure relief and ventilation is arranged on a pipeline between the gas pretreatment assembly and the vacuum drying box, and the valve D and the gas pretreatment assembly are controlled by the automatic controller;

the vacuum pump is controlled by the automatic controller, a temperature sensor for monitoring the temperature of the vacuum pump is arranged on the vacuum pump, and the temperature sensor is connected with the automatic controller;

and a temperature sensor and a pressure sensor are arranged in the vacuum drying oven, and the temperature sensor and the pressure sensor are connected with the automatic controller.

2. The automatic control system of the vacuum drying oven according to claim 1, characterized in that: the refrigerating plate adopts a semiconductor for refrigeration.

3. The automatic control system of the vacuum drying oven according to claim 2, characterized in that: the gas pretreatment assembly comprises a heating jacket.

4. The automatic control system of the vacuum drying oven according to claim 3, characterized in that: the gas pretreatment module also comprises a drying and deoxidizing device.

5. The automatic control system of the vacuum drying oven according to claim 1, characterized in that: the front end of the vacuum pump is provided with a one-way valve.

6. The control method of the automatic control system of the vacuum drying oven according to any one of claims 1 to 5, characterized in that: the method is automatically executed by the controller according to corresponding commands, comprises a starting-up process and a shutdown process,

the starting-up process comprises the following steps: the refrigerating sheet starts to work → when reaching the target temperature → the valve D is closed → the valve B is closed → the valve C is closed → the vacuum pump is opened → the valve A is opened;

the shutdown process comprises the following steps: closing valve A → opening valve B → delaying for 5 seconds → closing the vacuum pump → opening valve C → draining liquid → closing the refrigeration sheet → waiting for the vacuum drying oven temperature to drop to room temperature → opening valve D.

7. The control method of the automatic control system of the vacuum drying oven according to claim 6, characterized in that: when monitoring that the condensate in the cold trap reaches the liquid level or the vacuum pump is overheated or the pump needs to be stopped intermittently in the drying process, the controller executes the process of stopping the vacuum pump: closing valve a → opening valve B → delaying 5 seconds → closing the vacuum pump → opening valve C → draining liquid for 30 seconds → closing the refrigeration sheet according to the pause time.

8. The control method of the automatic control system of the vacuum drying oven according to claim 7, characterized in that: when the vacuum in the drying box needs to be released in the drying process, the process of stopping the vacuum pump is executed firstly, and then the process of releasing the vacuum is executed: starting the gas pre-treatment assembly → opening valve D → releasing to the vacuum drying oven to reach the target pressure → closing valve D → closing the gas pre-treatment assembly.

Technical Field

The invention relates to a vacuum drying oven, in particular to an automatic control system and a control method of the vacuum drying oven.

Background

The vacuum drying oven is widely applied to industries such as chemical industry, electronic communication, plastics, cables, electroplating, hardware, automobiles, photoelectricity, rubber products, molds, spraying, printing, medical treatment, aerospace and universities and colleges. Vacuum drying ovens generally contain a cold trap, which is a trap that traps gas in a condensed manner on a cooled surface, and is a device placed between the vacuum vessel and the pump for adsorbing gas or trapping oil vapor. The vacuum drying oven has strict operation step specifications in the use process, and the operation is manual operation, so that operation errors are easy to occur, and irreparable results are caused. In addition, when laboratory vacuum drying is carried out, the cold trap is generally placed in cooling liquid, and the cold trap and the cooling liquid are usually put in a refrigerator in advance for freezing so as to obtain refrigerating capacity. Therefore, the existing vacuum drying oven has the following disadvantages: (1) the use is inconvenient, and cooling liquid needs to be prepared in advance; (2) the cold trap has no continuous refrigerating capacity, cooling liquid needs to be replaced in the drying process, and long-time vacuum drying cannot be carried out; (3) the cold trap has limited volume, cannot store a large amount of condensate, and needs to be stopped to clean the condensate; (4) manual operation is complicated, operation steps are easy to reverse, and particularly, misoperation is easy to occur when the vacuum pump is turned off, so that vacuum pump oil in the pump is sucked back into the vacuum drying box to pollute dried articles; (5) when gas in the replacement drying oven, manual vacuum release is needed, then steam in the replacement drying oven is replaced by vacuumizing, so that dried articles are easily oxidized, the vacuum drying effect is poor, and the efficiency is low.

Disclosure of Invention

In order to solve the technical problems mentioned in the background art, the invention provides an automatic control system of a vacuum drying oven and a control method of the automatic control system of the vacuum drying oven.

An automatic control system of a vacuum drying oven comprises a gas pretreatment component, the vacuum drying oven, a cold trap and a vacuum pump which are sequentially connected by pipelines, and also comprises an automatic controller,

the outer wall of the cold trap is wrapped with a refrigerating sheet for cooling the cold trap, and the refrigerating sheet is controlled by the automatic controller;

a valve A for communicating or cutting off the pipeline is arranged on the pipeline between the vacuum drying box and the cold trap and is controlled by the automatic controller;

a valve B is arranged on a pipeline of the cold trap and the vacuum pump and is controlled by the automatic controller, the cold trap is communicated with the vacuum pump in a closed state, and the cold trap and the vacuum pump are both communicated with the external atmosphere in an open state;

the bottom end of the cold trap is connected with a liquid discharge pipe for discharging condensate, and a valve C is arranged on the liquid discharge pipe and is controlled by the automatic controller;

a liquid level sensor connected with the controller to monitor the volume of the condensate in the cold trap is arranged in the cold trap;

a valve D for pressure relief and ventilation is arranged on a pipeline between the gas pretreatment assembly and the vacuum drying box, and the valve D and the gas pretreatment assembly are controlled by the automatic controller;

the vacuum pump is controlled by the automatic controller, a temperature sensor for monitoring the temperature of the vacuum pump is arranged on the vacuum pump, and the temperature sensor is connected with the automatic controller;

and a temperature sensor and a pressure sensor are arranged in the vacuum drying oven, and the temperature and pressure sensor is connected with the automatic controller.

Preferably, the refrigerating plate adopts a semiconductor for refrigeration.

Preferably, the gas pretreatment module comprises a heating jacket.

Preferably, the gas pretreatment module further comprises a drying and deoxidation device.

Preferably, the front end of the vacuum pump is provided with a one-way valve.

The invention also provides a control method of the automatic control system of the vacuum drying oven, which is automatically executed by the controller according to corresponding commands and comprises a starting-up process and a shutdown process,

the starting-up process comprises the following steps: the refrigerating sheet starts to work → when reaching the target temperature → the valve D is closed → the valve B is closed → the valve C is closed → the vacuum pump is opened → the valve A is opened;

the shutdown process comprises the following steps: closing valve A → opening valve B → delaying for 5 seconds → closing the vacuum pump → opening valve C → draining liquid → closing the refrigeration sheet → waiting for the vacuum drying oven temperature to drop to room temperature → opening valve D.

Furthermore, when the condensate in the cold trap reaches the liquid level or the vacuum pump is overheated or intermittent pump stopping is needed in the drying process, the controller executes the process of stopping the vacuum pump: closing valve a → opening valve B → delaying 5 seconds → closing the vacuum pump → opening valve C → draining liquid for 30 seconds → closing the refrigeration sheet according to the pause time.

Furthermore, when the vacuum in the drying oven needs to be released during the drying process, the process of stopping the vacuum pump is executed first, and then the process of releasing the vacuum is executed: starting the gas pre-treatment assembly → opening valve D → releasing to the vacuum drying oven to reach the target pressure → closing valve D → closing the gas pre-treatment assembly.

Compared with the manual control vacuum drying oven adopted in the prior art, the automatic control system and the control method of the vacuum drying oven have the following advantages:

(1) the 4 valves, the refrigerating sheet, the vacuum pump and the gas pretreatment assembly are controlled according to information fed back by the sensor, automatic linkage of the cold trap, the vacuum pump and the flow path valve is realized, automatic control is realized by adopting an automatic control method, the consequence caused by errors caused by the reversal of manual operation steps is avoided, and the manual monitoring and operation intensity is reduced to the minimum.

(2) The vacuum pump has the cold trap function, cools the pumped water vapor and the solvent vapor, prevents the water vapor or the solvent vapor from being pumped into the vacuum pump, protects the vacuum pump, and greatly prolongs the service life of the pump oil. The liquid level sensor can monitor the volume of the condensate, prevent the condensate from exceeding the volume, and when the condensate in the cold trap is excessive, the condensate can be discharged out of the cold trap through the valve C, so that the limitation of the volume of the cold trap is overcome.

(3) The temperature of the vacuum pump is monitored by the vacuum pump temperature sensor, the shutdown is controlled by the controller when the vacuum pump is overheated, the overheating of the vacuum pump is prevented, the overheating protection of the vacuum pump is realized, and the service life of the vacuum pump is prolonged.

(4) The front end of the vacuum drying box is provided with a gas pretreatment assembly, the pretreatment assembly comprises a heating sleeve and a drying and deoxidizing device, when the gas in the drying box needs to be replaced, a valve D is opened to introduce deoxidized and dried air or inert gas, and the phenomenon that the sample is oxidized due to vacuum release when the temperature of the sample is too high is prevented;

(5) the temperature and pressure sensor in the vacuum drying oven can monitor the temperature and pressure in the vacuum drying oven, the vacuum pump is automatically closed when the vacuum drying oven reaches the target vacuum degree, and the vacuum pump is automatically opened when the vacuum drying oven is lower than the target vacuum degree, so that the best drying effect is kept, meanwhile, the service life of the vacuum pump is prolonged, and energy is saved.

(6) A valve B is arranged on a pipeline bypass pipe for connecting the cold trap and the vacuum pump, and the opening and closing of the valve B are controlled by a controller, so that the oil of the hollow pump in the vacuum pump can be prevented from being sucked back into the cold trap or the vacuum drying box when the vacuum pump is closed; the front end of the vacuum pump is provided with a physical one-way valve, the one-way valve is opened when the vacuum pump is opened, the one-way valve is closed when the vacuum pump is closed, and the oil of the vacuum pump can still be prevented from being sucked backwards under the accidental conditions of power failure and the like.

(7) The refrigeration piece is wrapped on the outer wall of the cold trap to realize active refrigeration, the use is convenient, the pre-cooling cold trap is not needed in advance, the refrigeration piece can continuously refrigerate, and the vacuum drying can be carried out for a long time.

Drawings

FIG. 1 is a schematic view of an automatic control system of a vacuum drying oven according to the present invention;

in the figure: the device comprises a valve A1, a refrigerating sheet 2, a valve B3, a temperature sensor 4, a valve C5, condensate 6, a liquid level sensor 7, a one-way valve 8, an air inlet pipe 9, a drying and deoxidizing device 10, a heating sleeve 11, a valve D12 and a temperature and pressure sensor 13.

Detailed Description

The following describes in detail a preferred embodiment of the automatic control system of the vacuum drying oven according to the present invention with reference to the schematic diagram of the controller of the vacuum drying oven shown in fig. 1.

The utility model provides a vacuum drying oven automatic control system, includes gas pretreatment subassembly, vacuum drying oven, cold trap and the vacuum pump of pipe connection in proper order, still includes automatic control.

The outer wall of the cold trap is wrapped with a refrigerating sheet 2 for cooling the cold trap, and the refrigerating sheet 2 can adopt semiconductor refrigeration or other refrigeration methods well known to those skilled in the art. This refrigeration piece 2 by automatic control ware control, the controller is according to the refrigeration temperature control refrigeration piece 2 refrigeration cooling of setting for and carry out cooling to the cold-trap, realizes initiatively refrigerating, and convenient to use need not precooling cold-trap in advance, and refrigeration piece 2 can last the refrigeration, can carry out vacuum drying for a long time.

And a pipeline between the vacuum drying box and the cold trap is provided with a valve A1 for communicating or cutting off the pipeline, the valve A1 is controlled by the automatic controller, and is opened after the vacuum pump is started and closed before the vacuum pump is closed, so that the requirement of vacuum pumping is met, and the oil or condensate 6 of the vacuum pump can be prevented from being sucked backwards.

A valve B3 is arranged on a pipeline between the cold trap and the vacuum pump, and the valve B3 is controlled by the automatic controller. The valve B3 is used for communicating the pipeline with the atmosphere, therefore, the valve B3 can adopt a T-shaped three-way valve which is arranged on the pipeline connecting the cold trap and the vacuum pump, and defines the closed state that the cold trap is communicated with the vacuum pump and the open state that the cold trap and the vacuum pump are both communicated with the outside atmosphere; valve B3 may also be installed on a bypass line provided on the line connecting the cold trap to the vacuum pump, in which case valve B3 may be a conventional solenoid valve. The controller controls the opening and closing of the vacuum pump, so that the vacuum pump can be opened when the vacuum pump is closed to prevent the hollow pump oil in the vacuum pump from being sucked back into the cold trap or the vacuum drying box, and the valve B3 is opened to communicate the cold trap with the atmosphere, so that the condensate 6 can be conveniently discharged.

And a liquid discharge pipe for discharging the condensate 6 is connected to the bottom end of the cold trap, and a valve C5 is arranged on the liquid discharge pipe and is controlled by the automatic controller C5. When the vacuum pump is stopped, valve a1 is closed, valve B3 is opened to vent the cold trap to atmosphere and the controller opens valve C5 to allow the condensate 6 in the cold trap to drain.

The cold trap is internally provided with a liquid level sensor 7 which is connected with the controller to monitor the volume of the condensate 6 in the cold trap, and the cold trap continuously condenses the steam evaporated by the dried articles along with the drying process, thereby avoiding that the steam or oil steam is sucked into the vacuum pump and mixed into the vacuum pump oil to influence the performance of the vacuum pump and shorten the service life of the vacuum pump oil. When the condensate 6 exceeds the maximum storage capacity of the cold trap, the condensate 6 can be conveniently discharged through the valve C5 arranged by the invention and the automatically controlled condensate 6 discharging program, and the drying process is not influenced.

A valve D12 for pressure release and ventilation is arranged on a pipeline between the gas pretreatment assembly and the vacuum drying box, and the valve D12 and the gas pretreatment assembly are controlled by the automatic controller. The front end of the vacuum drying box is provided with an air inlet pipe 9, the air inlet pipe 9 is provided with a gas pretreatment assembly, the pretreatment assembly comprises a heating sleeve 11 and a drying and deoxidizing device 10, when the gas in the drying box needs to be replaced, a valve D12 is opened to introduce deoxidized and dried air or inert gas, and the phenomenon that the sample is oxidized due to the fact that vacuum is released when the temperature of the sample is too high is avoided. Opening valve D12 after the drying process is completed balances the air pressure in the vacuum drying oven, facilitating the opening of the vacuum drying oven lid.

The vacuum pump is controlled by the automatic controller, a temperature sensor 4 for monitoring the temperature of the vacuum pump is arranged on the vacuum pump, and the temperature sensor 4 is connected with the automatic controller. Generally, the temperature sensor 4 can be disposed on the radiator, and in order to more accurately monitor the temperature of the vacuum pump, the temperature sensor 4 can be disposed to monitor the temperature of the vacuum pump oil. When the vacuum pump is overheated, the controller controls the shutdown to prevent the vacuum pump from overheating, realize the overheating protection of the vacuum pump and prolong the service life of the vacuum pump.

And a temperature and pressure sensor 13 is arranged in the vacuum drying box, and the temperature and pressure sensor 13 is connected with the automatic controller. When the vacuum drying oven reaches the target vacuum degree, the vacuum pump is automatically closed, and when the vacuum drying oven is lower than the target vacuum degree, the vacuum pump is automatically opened so as to keep the best drying effect, prolong the service life of the vacuum pump and save energy.

In order to avoid accidents such as system power failure, the front end of the vacuum pump is provided with a one-way valve 8, and the oil of the vacuum pump can be prevented from being sucked back through the automatic closing action of the one-way valve 8 even in the power failure situation.

The invention also provides a control method of the automatic control system of the vacuum drying oven, which is automatically executed by the controller according to corresponding commands and comprises a starting-up process and a shutdown process,

the starting-up process comprises the following steps: the refrigerating sheet starts to work → when reaching the target temperature → the valve D is closed → the valve B is closed → the valve C is closed → the vacuum pump is opened → the valve A is opened;

the shutdown process comprises the following steps: closing valve A → opening valve B → delaying for 5 seconds → closing the vacuum pump → opening valve C → draining liquid → closing the refrigeration sheet → waiting for the vacuum drying oven temperature to drop to room temperature → opening valve D.

When monitoring that the condensate in the cold trap reaches the liquid level or the vacuum pump is overheated or the pump needs to be stopped intermittently in the drying process, the controller executes the process of stopping the vacuum pump: closing valve a → opening valve B → delaying 5 seconds → closing the vacuum pump → opening valve C → draining liquid for 30 seconds → closing the refrigeration sheet according to the pause time.

When the vacuum in the drying box needs to be released in the drying process, the process of stopping the vacuum pump is executed firstly, and then the process of releasing the vacuum is executed: starting the gas pre-treatment assembly → opening valve D → releasing to the vacuum drying oven to reach the target pressure → closing valve D → closing the gas pre-treatment assembly.

The control method of the automatic control system of the vacuum drying oven comprises a starting-up process, a shutdown process, a clearance shutdown process, a condensate discharging process, a vacuum pump overheating shutdown process and a vacuum (gas replacement) releasing process of the vacuum drying oven, wherein the processes cover all requirements of the vacuum drying oven, all operation steps are controlled by the system, the process of each operation step in the vacuum drying process is strict, the sequence of each action is determined, the workload of personnel is reduced, and the loss caused by manual misoperation is avoided.

The control method of the automatic control system of the vacuum drying oven is only an optimal embodiment, is particularly suitable for the vacuum drying oven for the laboratory, and can also be suitable for the general vacuum drying oven. It will be apparent to those skilled in the art that modifications of the conventional art based on the disclosure of the present invention are included in the scope of the present invention.