CN117824879A - A high-precision seawater constant temperature tank device - Google Patents

Abstract

The invention discloses a high-precision seawater thermostatic bath device, wherein a high-power heater, a low-power heating wire and a stirring impeller are arranged in a thermostatic bath main body; the water chilling unit is used for directly cooling water in the constant temperature tank main body and sending the water back to the inside of the constant temperature tank main body; the circulating bath is used for carrying out heat exchange and cooling on water in the constant-temperature tank main body by using a cooling medium, and providing a constant-temperature and constant-flow cold source for the constant-temperature tank main body; the surface of the thermostatic bath main body is also nested with a micro industrial personal computer, and the micro industrial personal computer comprises a man-machine interaction interface, a temperature control circuit board, a high-precision thermistor thermometer and a master switch. The high-precision seawater thermostatic bath device can automatically regulate and control water temperature, realize accurate temperature control of submK level, ensure constant temperature environment required in the calibration process of equipment such as a marine thermometer or a temperature and salt depth measuring instrument, and solve the problems of poor temperature fluctuation and temperature field uniformity, small working area, long temperature control experiment time, lower automation degree and the like of the conventional thermostatic seawater bath.

Description

A high-precision seawater constant temperature tank device

Technical Field

The invention relates to the technical field of temperature measurement equipment calibration, and in particular to a high-precision seawater constant temperature tank device.

Background technique

Temperature is a key parameter reflecting the state of the ocean. Accurate measurement of ocean temperature is indispensable for national defense security, climate change, resource development and other fields. The seawater temperature is between -5℃ and 35℃. For the deep sea, which accounts for 90% of the total volume of seawater, the temperature is quite constant in space due to its huge heat capacity. It is estimated that the typical temperature change in the deep sea is 1mK every decade, that is, the annual average change is only about 0.1mK. Such high-quality hydrological measurements not only require very stable temperature sensors, but also place extremely high demands on measurement and metrology technology. The temperature-salinity-depth meter is an indispensable key equipment for ocean temperature measurement. The international mainstream temperature-salinity-depth meter, such as the SBE 911 series of the American Seabird Company, has a diameter of about 33cm and a height of about 95cm. It has large requirements for the size of the thermostatic bath working area, which cannot be accommodated by ordinary thermostatic baths on the market. In addition, according to the JJG763-2019 calibration procedure for temperature-salinity-depth meters, the calibration of the temperature-salinity-depth meter requires a high-precision seawater thermostatic bath as the main supporting equipment. High-precision seawater constant temperature bath is used to simulate actual ocean conditions and provide a highly stable constant temperature environment with a temperature range of at least -2°C to 40°C. The temperature control fluctuation and temperature field uniformity must be better than 1mK to achieve accurate calibration of the temperature-salinity-depth measuring instrument.

Existing thermostatic baths tend to have a smaller volume and are suitable for the calibration of industrial temperature sensors such as platinum resistance thermometers. They use an integrated structure with the bath body, temperature control system, compressor, heater, etc. integrated together, which limits their ability to accommodate large ocean temperature sensors. In large-capacity thermostatic baths, the working area is usually designed in a cubic shape, with the stirring blades placed at the bottom or side. This design may cause local hot spots or cold spots to appear inside the thermostatic bath, that is, the temperature control in some areas is not ideal, while other areas are too sensitive to temperature changes. This uneven temperature distribution may affect the consistency and accuracy of the measurement. This structural feature makes the area with the most constant temperature field the center of the working area, limiting the thermostatic bath to only accommodate a single measuring device at the same time.

In addition, the existing thermostatic bath heating wire and refrigeration system have relatively small cooling power. It takes a long time to reach a stable state when adjusting to a new temperature point. The change of the thermostatic bath temperature point (such as from -5°C to 35°C) may take several hours. Some high-precision thermostatic baths use a main heater and a high-power cold water tank to quickly change the temperature, and then use a low-power auxiliary heater and a temperature-controlled auxiliary tank for precise temperature control. Although the high-power cold water tank is connected to the working area of the main tank, the two are not liquid-connected. It only provides a cold source through the pipeline and uses heat conduction for cooling. The cooling efficiency is limited and the cooling time is long. The fast heater used for rapid heating is 3 discretely distributed heating rods, which is prone to uneven heating for large-capacity tanks. The temperature-controlled heater and auxiliary tank used for temperature control are both located at the bottom of the thermostatic bath. Even with stirring and drainage, it is easy to cause uneven vertical temperature field distribution in a large range of space.

In addition, the existing thermostatic bath has an independent cabinet equipped with multiple switch buttons, which is complex to operate and has a low degree of automation. For different target temperatures, the temperature and switch time of the main heating, auxiliary heating, main cooling and auxiliary cooling need to be manually adjusted, which places high demands on personnel.

Summary of the invention

In view of the deficiencies of the prior art, the present invention aims to provide a high-precision seawater constant temperature tank device.

In order to achieve the above object, the present invention adopts the following technical solution:

A high-precision seawater thermostatic bath device, comprising a thermostatic bath body, a chiller and a circulating bath;

A high-power heater, a low-power heating wire and a stirring impeller are arranged in the main body of the thermostatic bath;

The water chiller and the circulating bath are both connected to the interior of the thermostatic bath body through water pipes, and each water pipe is provided with an automatic valve; the water chiller is used to directly cool the water in the thermostatic bath body and return it to the interior of the thermostatic bath body; the circulating bath is used to use a cooling medium to perform heat exchange cooling on the water in the thermostatic bath body, thereby providing a constant temperature and constant flow cold source for the thermostatic bath body;

A micro industrial computer is also embedded on the surface of the thermostatic bath body, and the micro industrial computer includes a human-computer interaction interface, a temperature control circuit board, a high-precision thermistor thermometer and a main switch. The high-power heater, low-power heating wire, human-computer interaction interface, high-precision thermistor thermometer, main switch, chiller, circulating bath and automatic valve are all connected to the temperature control circuit board.

Furthermore, universal wheels are provided at the bottom of the thermostatic bath body.

Furthermore, the top of the thermostatic bath body is open and is provided with a closable bath cover.

Furthermore, the thermostatic bath body is cylindrical, and its inner diameter is 0.7-1.2m.

Furthermore, the low-power heating wire is arranged as a double-helix structure; and the high-power heater adopts a high-power flange-type electric heater.

Furthermore, the tank cover of the thermostatic tank body adopts a four-petal structure.

Furthermore, the water pipe and the thermostatic bath body are both made of titanium alloy material.

Furthermore, a mesh plate and a porous structure are arranged inside the thermostatic bath body; the mesh plate is arranged at the center position inside the thermostatic bath body and on both sides of the low-power heating wire and the stirring impeller; and the porous structure is arranged between the mesh plates on both sides.

The present invention also provides a single-point control method for the above-mentioned high-precision seawater thermostatic tank device, the specific process is:

A1. The user sets the target temperature T ₀ on the temperature control circuit board through the human-computer interaction interface. The temperature control circuit board reads the current internal temperature T _n of the thermostatic bath body through a high-precision thermistor thermometer and automatically sets the PID parameters using the self-tuning function.

A2. The temperature control circuit board keeps the internal temperature of the thermostatic bath body within the target temperature range by matching the output duty cycle of the low-power heating wire and the temperature of the circulating bath. If |T ₀ -T _n |＞1, it is determined that a high-power heater or a chiller is needed for temperature adjustment. At this time, according to the relationship between T ₀ and T _n , if T ₀ ＞T _n , the high-power heater is started to achieve rapid temperature increase. When |T ₀ -T _n |<0.5, the high-power heater is turned off. On the contrary, if T ₀ ＜T _n , the chiller is started to achieve rapid temperature reduction until |T ₀ -T _n |≤1, and the chiller is turned off.

The present invention also provides a multi-point control method for the above-mentioned high-precision seawater thermostatic tank device, the specific process is:

B1. The user sets the target temperature of multiple experiments and the corresponding experimental duration and stability requirements through the human-computer interaction interface according to the experimental requirements;

B2. For the target temperature of the first experiment, the temperature control circuit board completes the experiment of the corresponding set time through single-point control, then automatically switches to the next target temperature, and repeats the single-point control process to complete the experiment of the corresponding set time;

B3. Until all experiments are completed, the human-computer interaction interface gives a prompt;

The single-point control process for each target temperature T ₀ is as follows:

The temperature control circuit board reads the current internal temperature T _n of the thermostatic bath body through a high-precision thermistor thermometer and automatically sets the PID parameters using the self-tuning function;

The temperature control circuit board keeps the internal temperature of the thermostatic bath body within the target temperature range by matching the output duty cycle of the low-power heating wire and the temperature of the circulating bath; if |T ₀ -T _n |＞1, it is determined that a high-power heater or a chiller is needed for temperature adjustment; at this time, according to the relationship between T ₀ and T _n , if T ₀ ＞T _n , the high-power heater is started to achieve rapid temperature increase; when |T ₀ -T _n |<0.5, the high-power heater is turned off; conversely, if T ₀ ＜T _n , the chiller is started to achieve rapid temperature reduction until |T ₀ -T _n |≤1, and the chiller is turned off.

The beneficial effects of the present invention are as follows: the high-precision seawater thermostatic tank device of the present invention can automatically adjust the water temperature and achieve sub-mK level precise temperature control, thereby ensuring the constant temperature environment required during the calibration of temperature sensing equipment such as ocean thermometers or temperature-salinity-depth measuring instruments. The present invention can effectively solve the problems of temperature control fluctuation and poor temperature field uniformity, small working area, long temperature control experiment time and low degree of automation existing in the existing constant temperature seawater tank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a high-precision seawater thermostatic tank device in Example 1 of the present invention;

FIG2 is a flow chart of a method according to Embodiment 2 of the present invention;

FIG3 is a flow chart of a method according to Embodiment 3 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

Example 1

The present embodiment provides a high-precision seawater thermostatic bath device, which is suitable for the calibration of temperature sensing devices such as temperature-salinity-depth measuring instruments and ocean thermometers. The high-precision seawater thermostatic bath device of the present embodiment can automatically adjust the water temperature to achieve sub-millikelvin (mK) level temperature control accuracy, ensuring that the required constant temperature environment is provided during the calibration process of temperature sensing devices such as temperature-salinity-depth measuring instruments and ocean thermometers.

As shown in FIG1 , the high-precision seawater thermostatic bath device comprises a thermostatic bath body 4 , a circulating bath 1 and a chiller 16 ;

The thermostatic bath body 4 is provided with a high-power heater 5, a mesh plate 8, a low-power heating wire 9, a stirring impeller 10 and a porous structure 11;

The circulating bath 1 and the chiller 16 are both connected to the interior of the thermostatic bath body 4 through the water pipe 2, and each water pipe 2 is provided with an automatic valve 3; the chiller 16 is used to directly cool the water in the thermostatic bath body 4 and send it back to the interior of the thermostatic bath body 4; the circulating bath is used to use the cooling medium to perform heat exchange cooling on the water in the thermostatic bath body 4, and provide a constant temperature and constant flow cold source for the thermostatic bath body 4;

A micro industrial computer is also embedded on the surface of the thermostatic bath body 4, and the micro industrial computer includes a human-computer interaction interface 12, a temperature control circuit board 13, a high-precision thermistor thermometer 15 and a main switch 14. The high-power heater 5, the low-power heating wire 9, the human-computer interaction interface 12, the high-precision thermistor thermometer 15, the main switch 14, the circulating bath 1, the chiller 16 and the automatic valve 3 are all connected to the temperature control circuit board 13.

It should be noted that the working medium of the circulating bath is anhydrous ethanol, and its temperature is 2-3°C lower than the water in the thermostatic bath body. The chiller has a refrigeration capacity of 20kW, and the chiller directly participates in the water circulation when working, that is, after starting to work, the water in the thermostatic bath body 4 is directly sent to the chiller for rapid cooling and then sent back to the thermostatic bath body 4, so as to achieve the demand of rapidly lowering the water temperature.

By setting up a circulating bath and a chiller, the chiller can be started at the stage where rapid cooling is required to achieve rapid cooling of the water inside the thermostatic bath body. After reaching the target temperature, the chiller is stopped and the circulating bath continues to run to maintain the temperature stability inside the thermostatic bath body.

In this embodiment, universal wheels 6 are provided at the bottom of the thermostatic bath body 4 to facilitate movement of the device.

In this embodiment, the top of the thermostatic bath body 4 is open and is provided with an openable and closable bath cover 7 .

In this embodiment, the thermostatic bath body 4 adopts a cylindrical structure design, which optimizes the annular flow of water and creates a larger working area, so that multiple experiments can be carried out simultaneously at the same diameter level, thereby improving the use efficiency of the equipment. The size of the thermostatic bath body 4 can be changed according to demand. In this embodiment, the inner diameter of the thermostatic bath body 4 is 0.7-1.2m, which can accommodate most commercially available ocean thermometers and temperature-salinity-depth measuring instruments.

Furthermore, in this embodiment, the tank cover 7 of the thermostatic tank body 4 adopts a four-petal structure, which is easy to open and close, and is suitable for calibrating multiple temperature-salinity-depth meters at the same time.

More specifically, the high-precision thermistor thermometer 15 uses a high-stability NTC thermistor, whose annual drift is less than 1mK, and the temperature measurement accuracy can reach 0.8mK (the measurement range is -2°C to 35°C, k=2). The high-precision thermistor thermometer 15 is installed at the center of the thermostatic bath body 4, and is used in conjunction with the temperature control circuit board 13 with a high sampling frequency (greater than 3Hz) to achieve real-time monitoring and control of the temperature inside the thermostatic bath body.

In this embodiment, the power of the low-power heating wire 9 is 2200w, and it is set to a double-helix structure, which is adjusted through a precise PID control loop to achieve different degrees of temperature control.

In this embodiment, the high-power heater 5 is a high-power flange-type electric heater with a voltage of 380V, which can achieve high-speed heating.

It should be noted that by providing the high-power heater 5 and the low-power heating wire 9, the high-power heater 5 is activated when rapid temperature rise is required, and when the target temperature is approached, the high-power heater 5 is cut off, and the low-power heating wire 9 is continued to be used for fine temperature adjustment. By matching the output duty cycle of the low-power heating wire and the appropriate energy of the circulating bath, the precise temperature can be stably maintained.

In this embodiment, the rotation speed of the stirring impeller 10 is adjustable, and the user can adjust the stirring intensity according to actual needs to ensure that the water body can be evenly mixed, thereby eliminating or reducing the temperature gradient caused by temperature stratification or local hot spots.

Furthermore, in this embodiment, the internal structure design of the thermostatic bath body takes into account the principles of fluid mechanics, and a mesh plate 8 and a porous structure 11 are provided inside the thermostatic bath body. The mesh plate 8 is arranged at the center of the thermostatic bath body 4 and on both sides of the low-power heating wire and the stirring impeller, and its function is to evenly disperse the flow rate generated by the stirring impeller, prevent the water flow from directly impacting the inner wall of the thermostatic bath body or generating a large vortex in the thermostatic bath body; the porous structure 11 is arranged between the mesh plates 8 on both sides, further ensuring that the water flow can be evenly distributed in the entire thermostatic bath body, and the liquid flow in the thermostatic bath body maintains a dynamic flow rate, thereby effectively avoiding the cold and hot end phenomenon that may occur in the temperature field, and ensuring that the temperature field in the entire thermostatic bath body can be maintained in an extremely uniform state.

In this embodiment, the water pipe 2 and the thermostatic bath body 4 are both made of titanium alloy. Titanium alloy is known for its excellent corrosion resistance and is particularly suitable for resisting the corrosion effects of complex environments such as seawater. Such material selection not only prolongs the service life of the equipment, but also reduces maintenance costs, ensuring the stability and reliability of the seawater thermostatic bath device during long-term operation.

Example 2

This embodiment provides a single-point control method for the high-precision seawater thermostatic tank device described in Embodiment 1, and the specific process is shown in FIG. 2 .

First, the user sets the target temperature (T ₀ ) on the temperature control circuit board 13 through the human-machine interface 12 , and the temperature control circuit board 13 reads the current internal temperature (T _n ) of the thermostatic bath body through the high-precision thermistor thermometer 15 , and automatically sets the PID parameters using the self-tuning function;

Subsequently, the temperature control circuit board 13 keeps the internal temperature of the thermostatic bath body 4 within the target temperature range by matching the output duty cycle of the low-power heating wire 9 and the temperature of the circulating bath 1; if |T ₀ -T _n |＞1, it is determined that a high-power heater 5 or a chiller 16 is required for temperature adjustment; at this time, according to the relationship between T ₀ and T _n , if T ₀ ＞T _n , the high-power heater 5 is started to achieve rapid temperature increase; when |T ₀ -T _n |<0.5, the high-power heater is turned off; otherwise, if T ₀ ＜T _n , the chiller is started to achieve rapid temperature reduction until |T ₀ -T _n |≤1, the chiller is turned off. The temperature control circuit board 13 can display the temperature curve and real-time temperature standard deviation data (within 15 minutes) on the human-computer interaction interface 12 for the user to view.

Example 3

This embodiment provides a multi-point control method for the high-precision seawater thermostatic tank device described in Embodiment 1, and the specific process is shown in FIG3 :

First, the user can set the target temperature of multiple experiments and the corresponding experimental duration and stability requirements through the human-computer interaction interface 12 according to the experimental requirements;

Then the temperature control circuit board 13 reads the current internal temperature T _n of the thermostatic bath body through the high-precision thermistor thermometer 15, and controls the internal temperature of the thermostatic bath body according to the single-point control method described in Example 2 to make it reach the first target temperature T ₀₁ , and calculates the standard deviation of the temperature data within 15 minutes;

After reaching the set experimental time corresponding to the first target temperature T ₀₁ , the temperature control circuit board 13 automatically switches to the next target temperature T ₀₂ , and starts the single-point control process again;

Repeat the above process until the experiment is completed for each target temperature. At this time, the human-computer interaction interface provides corresponding prompts.

For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims (10)

1. The high-precision seawater thermostatic bath device is characterized by comprising a thermostatic bath main body, a water chilling unit and a circulating bath;

a high-power heater, a low-power heating wire and a stirring impeller are arranged in the constant temperature tank main body;

the water chiller and the circulating bath are communicated with the inside of the constant temperature tank main body through water pipes, and each water pipe is provided with an automatic valve; the water chilling unit is used for directly cooling water in the constant temperature tank main body and sending the water back to the inside of the constant temperature tank main body; the circulating bath is used for carrying out heat exchange and cooling on water in the constant-temperature tank main body by using a cooling medium, and providing a constant-temperature and constant-flow cold source for the constant-temperature tank main body;

the surface of the constant temperature tank main body is also nested with a micro industrial personal computer, the micro industrial personal computer comprises a man-machine interaction interface, a temperature control circuit board, a high-precision thermistor thermometer and a master switch, and the high-power heater, the low-power heating wire, the man-machine interaction interface, the high-precision thermistor thermometer, the master switch, the water chilling unit, the circulation bath and the automatic valve are all connected with the temperature control circuit board.

2. The high precision seawater thermostatic bath apparatus of claim 1, wherein the bottom of the thermostatic bath body is provided with universal wheels.

3. The high-precision seawater thermostatic bath apparatus according to claim 1, wherein the top of the thermostatic bath main body is opened and provided with a openable and closable bath cover.

4. The high-precision seawater thermostatic bath apparatus according to claim 1, wherein the thermostatic bath main body has a cylindrical shape with an inner diameter of 0.7-1.2m.

5. The high-precision seawater thermostatic bath apparatus according to claim 1, wherein the low-power heating wire is provided in a double-screw structure; the high-power heater adopts a high-power flange type electric heater.

6. A high-precision seawater thermostatic bath apparatus according to claim 3, wherein the bath cover of the thermostatic bath main body adopts a four-flap structure.

7. The high precision seawater thermostatic bath apparatus of claim 1 wherein the water tube and the thermostatic bath body are each made of a titanium alloy material.

8. The high-precision seawater thermostatic bath apparatus according to claim 1, wherein a mesh plate and a porous structure are provided inside the thermostatic bath main body; the mesh plate is arranged at the center position inside the thermostatic bath main body and is arranged at two sides of the low-power heating wire and the stirring impeller; the porous structure is arranged between the mesh plates at the two sides.

9. A single point control method of the high-precision seawater thermostatic bath device according to any one of claims 1 to 8, which is characterized by comprising the following specific steps:

a1, a user sets a target temperature T on a temperature control circuit board through a man-machine interaction interface ₀ The temperature control circuit board reads the internal temperature T of the current constant temperature tank main body through a high-precision thermistor thermometer _n And automatically setting PID parameters by utilizing the self-tuning function;

a2, the temperature control circuit board is kept in the internal temperature of the constant temperature tank main body within a target temperature range by matching the output duty ratio of the low-power heating wire and the temperature of the circulating bath; if |T ₀ -T _n The I is more than 1, and the temperature adjustment is judged to be needed by adopting a high-power heater or a water chilling unit; at this time, according to T ₀ And T is _n In relation to T ₀ ＞T _n Starting the high-power heater to realize rapid temperature rise; when it reaches |T ₀ -T _n |<0.5, closing the high-power heater; conversely, if T ₀ ＜T _n Starting the water chilling unit to realize rapid cooling until the temperature is |T ₀ -T _n And when the level is less than or equal to 1, the water chilling unit is closed.

10. A multipoint control method of the high-precision seawater thermostatic bath device according to any one of claims 1 to 8, which is characterized by comprising the following specific steps:

b1, setting target temperatures of a plurality of experiments and corresponding experiment duration and stability requirements by a user through a human-computer interaction interface according to experiment requirements;

b2, aiming at the target temperature of the first experiment, the temperature control circuit board completes the experiment of the corresponding set time length through single-point control, then automatically switches to the next target temperature, and repeats the single-point control process to complete the experiment of the corresponding set time length;

b3, giving a prompt by a human-computer interaction interface until all experiments are completed;

for each target temperature T ₀ The single point control process of (2) is as follows:

the temperature control circuit board reads the internal temperature T of the current constant temperature tank main body through a high-precision thermistor thermometer _n And automatically setting PID parameters by utilizing the self-tuning function;

the temperature control circuit board is used for keeping the internal temperature of the constant temperature tank main body within a target temperature range by matching the output duty ratio of the low-power heating wire and the temperature of the circulating bath; if |T ₀ -T _n The I is more than 1, and the temperature adjustment is judged to be needed by adopting a high-power heater or a water chilling unit; at this time, according to T ₀ And T is _n In relation to T ₀ ＞T _n Starting the high-power heater to realize rapid temperature rise; when it reaches |T ₀ -T _n |<0.5, closing the high-power heater; conversely, if T ₀ ＜T _n Starting the water chilling unit to realize rapid cooling until the temperature is |T ₀ -T _n And when the level is less than or equal to 1, the water chilling unit is closed.