CN214252173U - Sulfur hexafluoride gas moisture content detection device - Google Patents
Sulfur hexafluoride gas moisture content detection device Download PDFInfo
- Publication number
- CN214252173U CN214252173U CN202022602074.6U CN202022602074U CN214252173U CN 214252173 U CN214252173 U CN 214252173U CN 202022602074 U CN202022602074 U CN 202022602074U CN 214252173 U CN214252173 U CN 214252173U
- Authority
- CN
- China
- Prior art keywords
- sulfur hexafluoride
- electromagnetic valve
- hexafluoride gas
- moisture content
- detection device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Sampling And Sample Adjustment (AREA)
Abstract
The utility model discloses a sulfur hexafluoride gas moisture content detection device, which comprises an air inlet, an enrichment pool, a water measuring electrolytic cell, a heating element and an air collecting bag; the inlet of the enrichment pool is connected with the air inlet through a first electromagnetic valve, and an adsorbent for adsorbing moisture is arranged in the enrichment pool; the inlet of the water measuring electrolytic cell is connected with the outlet of the enrichment pool through a second electromagnetic valve and a third electromagnetic valve which are connected in sequence; the heating element is used for heating the enrichment tank to a specified temperature so that the moisture is completely desorbed from the adsorbent; the inlet of the air collecting bag is connected with the connecting point of the second electromagnetic valve and the third electromagnetic valve through a fifth electromagnetic valve, and the outlet of the air collecting bag is connected with the inlet end of the first electromagnetic valve through a fourth electromagnetic valve. The utility model discloses a moisture adsorbent "adsorbs-desorption again"'s mode, carries out the enrichment to sulfur hexafluoride gas moisture, has solved the gaseous karl fischer electrolysis method that the water content is low and is difficult to the measuring difficult problem, can reduce sulfur hexafluoride gas moisture content's detection limit, improves the precision that detects.
Description
Technical Field
The utility model belongs to the technical field of power equipment detects, concretely relates to gaseous moisture content detection device of sulfur hexafluoride.
Background
Sulfur hexafluoride gas has excellent insulating property, and is widely applied to various electric power equipment, and the higher the moisture content is, the greater the influence on the insulating property of the equipment is, and strict control is required. The existing sulfur hexafluoride moisture measurement methods mainly comprise a dew point method, a phosphorus pentoxide electrolysis method and a resistance-capacitance method. Wherein, hydrocarbon substance condensation influences the test result during the dew point method test; the phosphorus pentoxide electrolysis method has high drying requirement and is not suitable for field use; the resistance-capacitance method is obviously influenced by temperature and gas impurities. Therefore, it is urgently needed to develop a novel method and a novel device for detecting the moisture content of sulfur hexafluoride so as to realize accurate detection of the moisture content of sulfur hexafluoride gas.
SUMMERY OF THE UTILITY MODEL
To the problem, the utility model provides a sulfur hexafluoride gas moisture content detection device can realize sulfur hexafluoride moisture content's accurate detection, has vital effect to intervening insulating ageing of equipment in advance.
In order to realize the technical purpose, reach above-mentioned technological effect, the utility model discloses a following technical scheme realizes:
in a first aspect, the utility model provides a sulfur hexafluoride gas moisture content detection device, include:
an air inlet;
an inlet of the enrichment pool is connected with the air inlet through a first electromagnetic valve, and an adsorbent for adsorbing moisture in the sulfur hexafluoride gas is arranged inside the enrichment pool;
the inlet of the water measuring electrolytic cell is connected with the outlet of the enrichment pool through a second electromagnetic valve and a third electromagnetic valve which are connected in sequence;
the heating element is used for heating the enrichment tank to a specified temperature so as to completely desorb the moisture from the adsorbent;
and the inlet of the air collecting bag is connected with the connecting point of the second electromagnetic valve and the third electromagnetic valve through a fifth electromagnetic valve, and the outlet of the air collecting bag is connected with the inlet end of the first electromagnetic valve through a fourth electromagnetic valve.
Optionally, the sulfur hexafluoride gas moisture content detection device further comprises a first pressure sensor and a temperature sensor; and the first pressure sensor and the temperature sensor are connected with the enrichment pool and are used for measuring the pressure and the temperature inside the enrichment pool in real time.
Optionally, the sulfur hexafluoride gas moisture content detection device further comprises a second pressure sensor, and the second pressure sensor is connected with the gas collection bag.
Optionally, the sulfur hexafluoride gas moisture content detection device further comprises a gas flowmeter, and the gas flowmeter is arranged between the first electromagnetic valve and the gas inlet; and the fourth electromagnetic valve is connected with the inlet end of the gas flowmeter.
Optionally, the sulfur hexafluoride gas moisture content detection device further comprises a power supply and a switch, the heating element is sequentially connected with the power supply and the switch, and when the switch is closed, the heating element heats the enrichment pool to a specified temperature and keeps a constant temperature.
Optionally, the sulfur hexafluoride gas moisture content detection device further comprises a sealing pool and an exhaust port; the sealing pool is connected with the water measuring electrolytic cell, sealing liquid is arranged in the sealing pool, and the sealing liquid is hydrophobic liquid.
Optionally, the water measuring electrolytic cell comprises a cell body, and a first electrode, a second electrode, a stirrer and a karl fischer electrolyte are arranged in the cell body; the first and second electrodes are partially immersed in the karl fischer electrolyte; the stirrer is positioned inside the karl fischer electrolyte.
Optionally, the gas collection bag is a flexible bag.
In a second aspect, the present invention provides a method for detecting moisture content in sulfur hexafluoride gas based on any one of the first aspect, including:
opening the first electromagnetic valve, the third electromagnetic valve and the fifth electromagnetic valve, closing the second electromagnetic valve and the fourth electromagnetic valve, sending a certain amount of sulfur hexafluoride gas into the enrichment pool, adsorbing moisture contained in the sulfur hexafluoride gas by an adsorbent in the enrichment pool to realize drying, and enabling the dried sulfur hexafluoride gas to enter the gas collecting bag after coming out of the enrichment pool;
closing the first solenoid valve, the third solenoid valve and the fifth solenoid valve;
heating the enrichment pool to a preset temperature value by using a heating element, and keeping for a period of time to ensure that the moisture in the adsorbent is completely desorbed from the adsorbent to form water vapor;
and opening the third electromagnetic valve, the first electromagnetic valve, the second electromagnetic valve and the fourth electromagnetic valve, outputting a certain amount of dry sulfur hexafluoride gas by using the gas collecting bag to blow the enrichment pool, blowing the water vapor in the enrichment pool into the water measuring electrolytic cell until the detection is finished, and calculating the moisture content in the sulfur hexafluoride gas.
Optionally, the step of blowing the water vapor in the enrichment pool into the water measuring electrolytic cell until the detection is completed includes:
and blowing the water vapor in the enrichment pool to the bottom of a water measuring electrolytic cell, and measuring the water content of the water measuring electrolytic cell based on a Karl Fischer electrolytic method until the detection is finished.
Optionally, the step of outputting a certain amount of dry sulfur hexafluoride gas by using the gas collection bag to purge the enrichment pool specifically comprises the following steps:
the gas collection bag is squeezed so that a certain amount of dry sulfur hexafluoride gas sweeps the enrichment pool.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) the utility model discloses a moisture adsorbent "adsorbs-desorption again"'s mode, has realized the enrichment to moisture in the sulfur hexafluoride gas, has solved the gaseous karl Fischer electrolysis method that the water content is low and has been difficult to the measuring difficult problem, can effectively reduce the detection limit of the gaseous moisture content of sulfur hexafluoride, improves the precision and the sensitivity that detect, provides a new useful method for the measurement of the gaseous moisture of sulfur hexafluoride, and the important meaning has to pipe accuse aeration equipment moisture content, guarantee power equipment operation safety.
(2) The utility model provides a method based on karl fischer electrolysis principle is to sulfur hexafluoride gas moisture measurement, because before the sample measurement at every turn of karl fischer electrolysis method, can react earlier the moisture of background and reach the balance, carry out the test of sample again after the balance to the interference of environment moisture has been got rid of, method itself does not receive moisture in the environment and disturbs, and measuring speed is fast, it is convenient to use.
Drawings
In order that the present invention may be more readily and clearly understood, the following detailed description of the present invention is provided in connection with the accompanying drawings, in which:
fig. 1 is a schematic structural view of a sulfur hexafluoride gas moisture content detection device according to an embodiment of the present invention;
the meanings of the symbols in the figures:
1-enrichment pool, 2-heating element, 3-power supply, 4-switch, 5-water measuring electrolytic cell, 6-stirrer, 7-first electrode, 8-second electrode, 9-sealing pool, 10-air collecting bag, 11-first electromagnetic valve, 12-third electromagnetic valve, 13-second electromagnetic valve, 14-fourth electromagnetic valve, 15-gas flowmeter, 16-first pressure sensor, 17-temperature sensor, 18-second pressure sensor, 19-air inlet, 20-air outlet and 21-fifth electromagnetic valve.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the scope of the invention.
The following description is made in detail for the application of the principles of the present invention with reference to the accompanying drawings.
Example 1
As shown in fig. 1, the embodiment of the present invention provides a sulfur hexafluoride gas moisture content detection device, including:
an air inlet 19;
an inlet of the enrichment pool 1 is connected with the air inlet 19 through a first electromagnetic valve 11, and an adsorbent for adsorbing moisture in the sulfur hexafluoride gas is arranged inside the enrichment pool;
the inlet of the water measuring electrolytic cell 5 is connected with the outlet of the enrichment pool 1 through a second electromagnetic valve 13 and a third electromagnetic valve 12 which are connected in sequence;
the heating element 2 is used for heating the enrichment tank 1 to a specified temperature so as to completely desorb the moisture from the adsorbent;
the air collecting bag 10 has an inlet connected to the connection point of the second solenoid valve 13 and the third solenoid valve 12 via a fifth solenoid valve 21, and an outlet connected to the inlet of the first solenoid valve 11 via a fourth solenoid valve 14.
In a specific implementation manner of the embodiment of the present invention, the device for detecting moisture content in sulfur hexafluoride gas further includes a first pressure sensor 16 and a temperature sensor 17; the first pressure sensor 16 and the temperature sensor 17 are both connected with the enrichment pool 1, and the pressure and the temperature in the enrichment pool 1 are measured in real time; the first pressure sensor 16 is used for monitoring the pressure in the enrichment pool 1, so that technicians can see the pressure in the enrichment pool 1 conveniently in the detection process, and abnormal conditions such as overlarge pressure and the like are prevented from being found; the temperature sensor 17 is used for monitoring the temperature of the enrichment pool 1, when the heating element 2 is heated, if the temperature reaches a target value, the heating element 2 is stopped, and when the temperature is lower than the target value, the heating element 2 is started for keeping the enrichment pool 1 in a certain temperature range to realize desorption of water on the adsorbent.
The embodiment of the utility model provides an in a specific implementation mode, sulfur hexafluoride gas moisture content detection device still includes second pressure sensor 18, second pressure sensor 18 with air collection bag 10 links to each other, and second pressure sensor 18 is used for measuring the pressure in air collection bag 10, also is used for the technical staff to observe, prevents that air collection bag 10 internal pressure is too big, sets up pressure sensor and mainly is the safety consideration.
In a specific implementation manner of the embodiment of the present invention, the device for detecting moisture content in sulfur hexafluoride gas further includes a gas flowmeter 15, and the gas flowmeter 15 is disposed between the first electromagnetic valve 11 and the air inlet 19; the fourth electromagnetic valve 14 is connected with an inlet end of the gas flowmeter 15, and the gas flowmeter 15 is used for quantifying the sulfur hexafluoride gas entering the enrichment pool 1 and controlling the volume of the sulfur hexafluoride gas entering the enrichment pool 1.
The utility model discloses in the embodiment of a concrete implementation mode, sulfur hexafluoride gas moisture content detection device still includes power 3 and switch 4, add heat-insulating material 2 with power 3, switch 4 connect gradually, work as when switch 4 is closed, add heat-insulating material 2 and heat to appointed temperature and keep constant temperature enriching pond 1 for realize moisture desorption completely from the adsorbent. In the specific implementation, a resistance wire can be selected as the heating element 2, and the heating element 2 is uniformly wound outside the enrichment pool 1.
In a specific implementation manner of the embodiment of the present invention, the device for detecting moisture content in sulfur hexafluoride gas further includes a sealed pool 9 and an exhaust port 20; the sealing pool 9 is connected with the water measuring electrolytic pool 5, sealing liquid is arranged in the sealing pool, and the sealing liquid is hydrophobic liquid and is used for preventing moisture in air from interfering the water measuring electrolytic pool 5.
In a specific implementation manner of the embodiment of the present invention, the water measuring electrolytic cell 5 includes a cell body, and a first electrode 7, a second electrode 8, a stirrer 6 and karl fischer electrolyte are disposed in the cell body; the first electrode 7 and the second electrode 8 are both partially immersed in the karl fischer electrolyte; the stirrer 6 is located inside the karl fischer electrolyte.
In a specific embodiment of the present invention, the air collecting bag 10 is a flexible bag, and can be used for collecting the sulfur hexafluoride gas entering, and the collected sulfur hexafluoride gas can be extruded and output by external force.
In a specific embodiment of the present invention, the enrichment pool 1 is a slender structure, and the interior of the enrichment pool is filled with sufficient adsorbents (such as molecular sieve, phosphorus pentoxide, etc.), which can effectively adsorb moisture in sulfur hexafluoride gas, and when the temperature of the adsorbents is higher than 100 ℃, the moisture can be completely desorbed from the adsorbents again.
To sum up, the embodiment of the utility model provides an in the working process of detection device specifically be:
opening a first electromagnetic valve 11, a third electromagnetic valve 12 and a fifth electromagnetic valve 21, closing a second electromagnetic valve 13 and a fourth electromagnetic valve 14, sending a certain amount of sulfur hexafluoride gas into the enrichment pool 1, preferably uniformly sending the sulfur hexafluoride gas into the top of the enrichment pool 1 through a flowmeter 15, adsorbing moisture contained in the sulfur hexafluoride gas by using an adsorbent in the enrichment pool 1 to realize drying, and enabling the dried sulfur hexafluoride gas to enter an air collecting bag 10 after coming out of the enrichment pool 1;
closing the first, third and fifth solenoid valves 11, 13, 21;
heating the enrichment pool 1 to a preset temperature value (120 ℃ or a temperature value higher than 100 ℃) by using the heating element 2, and keeping for a period of time to ensure that the moisture in the adsorbent is completely desorbed from the adsorbent to form water vapor;
and opening the third electromagnetic valve 12, the first electromagnetic valve 11, the second electromagnetic valve 13 and the fourth electromagnetic valve 14, blowing the enrichment pool 1 by using a certain amount (such as 500mL, which can be set according to actual requirements) of dry sulfur hexafluoride gas output by the gas collection bag 10, blowing the water vapor in the enrichment pool 1 into the water measuring electrolytic cell 5 until the detection is finished, and calculating the moisture content in the sulfur hexafluoride gas.
Example 2
The embodiment of the utility model provides a method based on any one of embodiment 1 gaseous moisture content detection device of sulfur hexafluoride, a serial communication port, include:
opening a first electromagnetic valve 11, a third electromagnetic valve 12 and a fifth electromagnetic valve 21, closing a second electromagnetic valve 13 and a fourth electromagnetic valve 14, sending a certain amount of sulfur hexafluoride gas into the enrichment pool 1, preferably, sending the sulfur hexafluoride gas into the enrichment pool 1 at a constant speed, preferably, sending the sulfur hexafluoride gas into the top of the enrichment pool 1 through a flowmeter 15, adsorbing moisture contained in the sulfur hexafluoride gas by an adsorbent in the enrichment pool 1 to realize drying, and sending the dried sulfur hexafluoride gas into an air collecting bag 10 after coming out of the enrichment pool 1;
closing the first, third and fifth solenoid valves 11, 12, 21;
heating the enrichment pool 1 to a preset temperature value (120 ℃ or a temperature value higher than 100 ℃) by using the heating element 2, and keeping for a period of time to ensure that the moisture in the adsorbent is completely desorbed from the adsorbent to form water vapor;
and opening the third electromagnetic valve 12, the first electromagnetic valve 11, the second electromagnetic valve 13 and the fourth electromagnetic valve 14, blowing the enrichment pool 1 by using a certain amount (such as 500mL, which can be set according to actual requirements) of dry sulfur hexafluoride gas output by the gas collection bag 10, blowing the water vapor in the enrichment pool 1 into the water measuring electrolytic cell 5 until the detection is finished, and calculating the moisture content in the sulfur hexafluoride gas.
In a specific embodiment of the present invention, blow the water vapor in the enrichment pool 1 to the water measuring electrolytic cell 5, until the detection is completed, calculate the moisture content in the sulfur hexafluoride gas, specifically be:
and blowing the water vapor in the enrichment pool 1 to the bottom of the water measuring electrolytic cell 5, measuring the moisture content of the water measuring electrolytic cell 5 based on a Karl Fischer electrolysis method until the detection is finished, and calculating the moisture content in the sulfur hexafluoride gas.
In a specific embodiment of the present invention, the enrichment pool 1 is purged by using the dry sulfur hexafluoride gas output by the air collecting bag 10 in a certain amount, specifically:
the air collecting bag 10 is extruded, so that a certain amount of dry sulfur hexafluoride gas sweeps the enrichment pool 1, and the operation is convenient.
The basic principles and the main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (8)
1. The utility model provides a sulfur hexafluoride gas moisture content detection device which characterized in that includes:
an air inlet;
an inlet of the enrichment pool is connected with the air inlet through a first electromagnetic valve, and an adsorbent for adsorbing moisture in the sulfur hexafluoride gas is arranged inside the enrichment pool;
the inlet of the water measuring electrolytic cell is connected with the outlet of the enrichment pool through a second electromagnetic valve and a third electromagnetic valve which are connected in sequence;
the heating element is used for heating the enrichment tank to a specified temperature so as to completely desorb the moisture from the adsorbent;
and the inlet of the air collecting bag is connected with the connecting point of the second electromagnetic valve and the third electromagnetic valve through a fifth electromagnetic valve, and the outlet of the air collecting bag is connected with the inlet end of the first electromagnetic valve through a fourth electromagnetic valve.
2. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the sulfur hexafluoride gas moisture content detection device further comprises a first pressure sensor and a temperature sensor; and the first pressure sensor and the temperature sensor are connected with the enrichment pool and are used for measuring the pressure and the temperature inside the enrichment pool in real time.
3. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the sulfur hexafluoride gas moisture content detection device further comprises a second pressure sensor, and the second pressure sensor is connected with the gas collection bag.
4. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the sulfur hexafluoride gas moisture content detection device further comprises a gas flowmeter, and the gas flowmeter is arranged between the first electromagnetic valve and the gas inlet; and the fourth electromagnetic valve is connected with the inlet end of the gas flowmeter.
5. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the sulfur hexafluoride gas moisture content detection device further comprises a power supply and a switch, the heating element is sequentially connected with the power supply and the switch, and when the switch is closed, the heating element heats the enrichment pool to a specified temperature and keeps the temperature constant.
6. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the sulfur hexafluoride gas moisture content detection device also comprises a sealing pool and an exhaust port; the sealing pool is connected with the water measuring electrolytic cell, sealing liquid is arranged in the sealing pool, and the sealing liquid is hydrophobic liquid.
7. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the water measuring electrolytic tank comprises a tank body, and a first electrode, a second electrode, a stirrer and a Karl Fischer electrolyte are arranged in the tank body; the first and second electrodes are partially immersed in the karl fischer electrolyte; the stirrer is positioned inside the karl fischer electrolyte.
8. The sulfur hexafluoride gas moisture content detection device according to claim 1, wherein: the air collecting bag is a flexible bag.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022602074.6U CN214252173U (en) | 2020-11-11 | 2020-11-11 | Sulfur hexafluoride gas moisture content detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022602074.6U CN214252173U (en) | 2020-11-11 | 2020-11-11 | Sulfur hexafluoride gas moisture content detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214252173U true CN214252173U (en) | 2021-09-21 |
Family
ID=77732018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022602074.6U Active CN214252173U (en) | 2020-11-11 | 2020-11-11 | Sulfur hexafluoride gas moisture content detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214252173U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115877197A (en) * | 2022-12-17 | 2023-03-31 | 武汉杭久电气有限公司 | Detection device for circuit breaker |
-
2020
- 2020-11-11 CN CN202022602074.6U patent/CN214252173U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115877197A (en) * | 2022-12-17 | 2023-03-31 | 武汉杭久电气有限公司 | Detection device for circuit breaker |
| CN115877197B (en) * | 2022-12-17 | 2023-07-14 | 武汉杭久电气有限公司 | Detection device for circuit breaker |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112345689A (en) | Sulfur hexafluoride gas moisture content detection device and method | |
| CN201867326U (en) | Sulfur hexafluoride (SF6) gas sampling detection device | |
| CN214252173U (en) | Sulfur hexafluoride gas moisture content detection device | |
| CN101476997A (en) | Sulfur hexafluoride gas sample collection apparatus | |
| CN102466636B (en) | Device for detecting marine volatile sulfur compounds with ultraviolet fluorescence method and manufacture method of device | |
| CN107192794A (en) | A kind of device of underground coal mine CO sources identification | |
| CN111781251A (en) | Device for measuring content of low-concentration gas in flue gas | |
| CN201348579Y (en) | Sulfur hexafluoride sample collection device | |
| CN103430015B (en) | Moisture content detection device | |
| CN210572144U (en) | Real-time measurement all-in-one of quality of water volatility organic matter | |
| CN209042916U (en) | A kind of drying box with gas collecting apparatus | |
| CN204388595U (en) | A kind of high-frequency induction combustion furnace | |
| CN208537338U (en) | A kind of Dewar bottle apparatus for isothermal adsorption instrument | |
| CN101169451B (en) | Integral multi-components fermented tail gas on-line detection device | |
| CN116678997A (en) | Multifunctional hydrogen sensor evaluation testing device and method | |
| CN112472069B (en) | Animal respiration heat measuring method and device | |
| CN212275539U (en) | Insulating silicon oil electricity-moisture composite aging experimental device for cable terminal | |
| CN211955222U (en) | COD (chemical oxygen demand) measuring device for high-chlorine water sample | |
| CN210356209U (en) | Suction filtration device for quantitatively analyzing change of water content of sludge combined water | |
| CN104374612B (en) | Constant-temperature rapid air sampling device and using method thereof | |
| CN207123424U (en) | Sampler and flue sampling system | |
| CN208109672U (en) | The low temperature test device of controllable temperature | |
| CN221238909U (en) | Real-time gas production detection device for soft package battery | |
| CN109975491A (en) | Sulfur trioxide/sulfuric acid method in a kind of isloation state detection flue gas | |
| CN216747241U (en) | Gas adsorption performance testing device capable of heating uniformly |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |