CN209944783U - High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber - Google Patents

High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber Download PDF

Info

Publication number
CN209944783U
CN209944783U CN201920328980.6U CN201920328980U CN209944783U CN 209944783 U CN209944783 U CN 209944783U CN 201920328980 U CN201920328980 U CN 201920328980U CN 209944783 U CN209944783 U CN 209944783U
Authority
CN
China
Prior art keywords
heat
heat absorber
power station
temperature
tower
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
Application number
CN201920328980.6U
Other languages
Chinese (zh)
Inventor
丁路
张保威
陈梁
陈红
林毅
孙登科
莫春鸿
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dongfang Boiler Group Co Ltd
Original Assignee
Dongfang Boiler Group Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Dongfang Boiler Group Co Ltd filed Critical Dongfang Boiler Group Co Ltd
Priority to CN201920328980.6U priority Critical patent/CN209944783U/en
Application granted granted Critical
Publication of CN209944783U publication Critical patent/CN209944783U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/40Solar thermal energy, e.g. solar towers

Landscapes

  • Buildings Adapted To Withstand Abnormal External Influences (AREA)

Abstract

The utility model discloses a tower light and heat power station heat absorber is with thermal-insulated protective structure of high temperature, thermal-insulated protective structure of high temperature includes braced frame and sets up respectively the inboard close-fitting outer inoxidizing coating in close-fitting seal heat preservation of braced frame and the outside, close-fitting seal heat preservation and the outer inoxidizing coating in close-fitting between be the air bed. The high-temperature heat insulation protection structure for the tower type photo-thermal power station heat absorber of the utility model optimizes the high-temperature heat insulation protection structure for the heat absorber, separates the heat insulation protection and the heat preservation function of the heat absorber, avoids the selection of high-cost protection materials and reduces the cost through the optimized design of the structure on the premise of ensuring the heat efficiency of the heat absorber; through structural reasonable vent that sets up, satisfy the heat absorber to ambient temperature and ventilation's demand when the extreme season of winter, summer operation, guarantee the security and the reliability of system and equipment operation.

Description

High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber
Technical Field
The utility model relates to a technical field of tower light and heat power station, more specifically say, relate to a tower light and heat power station heat absorber is with thermal-insulated protective structure of high temperature.
Background
For a tower type photo-thermal power station, the heat absorber mainly has the function of converting solar energy tracked, focused and reflected by a mirror field into heat energy capable of being efficiently utilized, and provides a heat source for a steam turbine generator unit at the rear end. The inside support steel of heat absorber constructs to be fixed in on the heat absorption tower platform, is heated the tube panel and hangs the outside that is fixed in the support steel structure for the direct radiation of the sunlight of absorption mirror field reflection, nevertheless to the support steel structure part of collection case and the non-effective heat absorption region about being heated the tube panel then need carry out thermal-insulated protection, the purpose prevents that the sunlight from spilling over or heliostat tracking error from causing the high temperature to construct and internally mounted equipment to steel and damaging.
Therefore, the heat insulation protective material for the heat absorber must adopt a white high-reflection material, and can reflect most of sunlight radiated by high heat flow to the surface; in addition, because the solar heat collector is installed outdoors, the solar heat collector has strong ultraviolet irradiation resistance, outdoor rain, snow, strong wind, insolation and other alternate weather resistance, has high heat flow and sunlight dry burning resistance, and cannot crack or be damaged under temperature difference stress; with the daily start-stop and weather change of the heat absorber, the heat insulation protection also needs to bear at least one hot and cold alternating cycle every day. Overall, the working environment and the operating characteristics place higher demands on the materials and structures.
In addition, for the heat absorber, which belongs to a relatively closed environment, a plurality of electrical and thermal control systems and devices are arranged inside, but the operating temperatures of the systems or devices all have certain limiting requirements, namely, reasonable heating and ventilation conditions must be considered: in summer, under the conditions of high ambient temperature, high heat flow radiation bearing and external heat dissipation of a thermodynamic system, good ventilation must be considered so as to reduce the internal ambient working temperature of the heat absorber, ensure the safety of an electric control system or equipment and prolong the service life of the electric control system or equipment; in winter, especially in northwest areas with abundant solar energy resources, the environmental temperature is very low, and in order to maintain the internal working temperature of the heat absorber and improve the heat conversion efficiency of the heat absorber, better warm keeping and temperature maintaining measures are needed.
In a commercial photo-thermal power station operated abroad, a nano plate or a hard ceramic plate with a unique patented technology is usually adopted as a heat insulation protection plate, although the performance is superior, the cost is too high, which accounts for about one tenth of the overall investment cost of a heat absorber, and the later maintenance and replacement cost and the later period of equipment are difficult to meet the project requirements.
SUMMERY OF THE UTILITY MODEL
To the problem that exists among the prior art, the utility model provides a tower light and heat power station heat absorber is with thermal-insulated protective structure of high temperature to the special operational environment of heat absorber and operation demand.
The utility model provides a tower light and heat power station heat absorber is with thermal-insulated protective structure of high temperature, thermal-insulated protective structure of high temperature includes braced frame and sets up respectively the inboard close-fitting outer inoxidizing coating in close-fitting seal heat preservation of braced frame and the outside, close-fitting seal heat preservation and the outer inoxidizing coating in close-fitting between be the air bed.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, high temperature protective structure that insulates against heat arranges upper portion guard zone and the lower part guard zone in tower light and heat power station heat absorber effective heated area.
According to tower light and heat power station heat absorber is with an embodiment of the thermal-insulated protective structure of high temperature, close-fitting seal heat preservation is fixed in the interior on the inside support steel structure of upper portion guard area and lower part guard area.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, outer inoxidizing coating adopts high temperature resistant radiation, rain and snow to erode and the surface has the guard plate of high reflectivity.
According to tower light and heat power station heat absorber is with an embodiment of the thermal-insulated protective structure of high temperature, on the outer inoxidizing coating dorsal part was fixed in braced frame, braced frame was the modular structure design.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, outer inoxidizing coating is bilayer or multilayer structure, installs with the fissure of displacement pressure structural style between the adjacent layer.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, the outmost a plurality of counter bore that is provided with of outer inoxidizing coating, outer inoxidizing coating is fixed on braced frame through the fixing bolt who passes the counter bore.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, the counter bore intussuseption of installing fixing bolt is filled with sealing filler.
According to tower light and heat power station heat absorber is with an embodiment of high temperature protective structure that insulates against heat, the ventilation import that can open or close is evenly arranged along the hoop in the lower part of lower part guard space, the ventilation export has been arranged at the top of heat absorber.
The high-temperature heat insulation protection structure for the tower type photo-thermal power station heat absorber of the utility model optimizes the high-temperature heat insulation protection structure for the heat absorber, separates the heat insulation protection and the heat preservation function of the heat absorber, avoids the selection of high-cost protection materials and reduces the cost through the optimized design of the structure on the premise of ensuring the heat efficiency of the heat absorber; through structural reasonable vent that sets up, satisfy the heat absorber to ambient temperature and ventilation's demand when the extreme season of winter, summer operation, guarantee the security and the reliability of system and equipment operation.
Drawings
Fig. 1 shows an overall structure schematic diagram of a tower-type photothermal power station heat absorber with a high-temperature heat insulation protection structure according to an exemplary embodiment of the present invention after installation.
Fig. 2 shows a schematic structural view of a high-temperature thermal insulation protection structure for a tower type solar-thermal power station heat absorber according to an exemplary embodiment of the present invention.
Fig. 3 shows a schematic structural view of an outer shield plate in a high-temperature thermal insulation protection structure for a tower type solar-thermal power station heat absorber according to an exemplary embodiment of the present invention.
Description of reference numerals:
1-heat absorption tower, 2-heat absorption tower platform 3-internal support steel structure 4-upper protection zone, 5-effective heated zone, 6-back heat preservation layer, 7-ventilation inlet, 8-ventilation outlet, 9-lower protection zone, 41-internal close-fitting heat preservation layer, 42-external protection layer, 43-support frame, 4211-first protection plate inner layer, 4212-second protection plate inner layer, 4221-first protection plate outer layer, 4222-second protection plate outer layer and 423-fixing bolt.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
The high-temperature heat insulation protection structure for the tower type solar-thermal power station heat absorber of the present invention is specifically described and illustrated below.
Fig. 1 shows an overall structure schematic diagram of a tower-type photothermal power station heat absorber with a high-temperature heat insulation protection structure according to an exemplary embodiment of the present invention after installation.
As shown in fig. 1, the tower type photothermal power station heat absorber is arranged on a heat absorption tower 1, and is integrally divided into an effective heating area 5, an upper protection area 4 and a lower protection area 9, and an internal support steel structure 3 of the heat absorber is fixed on a heat absorption tower platform 2 and is used for supporting related system equipment, a heat receiving tube panel, a protection area structure and the like in the heat absorber.
Wherein, the effective heated area 5 is arranged with a heated tube panel, the heated tube panel is suspended and fixed outside the heat absorber, the heated tube panel directly bears the high heat flow solar radiation reflected by the heliostat, the inside is a flowing heat absorption working medium, which can be a water working medium, and can also be heat conduction oil, molten salt or liquid metal, etc. And a back heat-insulating layer 6 is laid on the backlight side of the heated tube panel and used for reducing heat loss so as to ensure the heat absorption efficiency of the heat absorber. The protection zones are arranged at the upper and lower positions of the effective heated zone 5, and the height and the structural size of each protection zone are related to the overall structural design of the heat absorber, the control precision of the heliostat, the operation strategy of a heliostat field and the like.
Fig. 2 shows a structural schematic diagram of a high-temperature thermal insulation protection structure for a tower type solar-thermal power station heat absorber according to an exemplary embodiment of the present invention, and fig. 3 shows a structural schematic diagram of an outer protection plate in the high-temperature thermal insulation protection structure for the tower type solar-thermal power station heat absorber according to an exemplary embodiment of the present invention.
As shown in fig. 1 and 2, according to an exemplary embodiment of the present invention, the high temperature thermal insulation protection structure for a tower type photothermal power station heat absorber includes a supporting frame 43 and an inner close-fitting closed thermal insulation layer 41 and an outer protection layer 42 respectively disposed at an inner side of the supporting frame 43, wherein an air layer is formed between the inner close-fitting closed thermal insulation layer 41 and the outer protection layer 42.
The utility model discloses an adopt bilayer structure design to protective structure, outer inoxidizing coating 42 that preferably adopts high temperature resistant radiation, resistant sleet to erode and the surface has characteristics such as higher reflectivity carries out thermal-insulated protection to the heat sink if the guard plate, and the inlayer then adopts the interior close-fitting heat preservation 41 that seals that conventional insulation material constitutes to keep warm to the heat sink and keep warm, is the air bed between inside and outside, utilizes the natural convection current of air to carry out ventilation cooling to reduce outer guard plate inboard wall temperature.
The utility model discloses a high temperature protective structure that insulates against heat arranges the upper portion guard interval 4 and the lower part guard interval 9 of effectively receiving the heat district 5 in tower light and heat power station heat absorber.
Specifically, the inner close-fitting heat insulating layer 41 is fixed to the inner support steel structure 3 of the upper and lower protection zones 4 and 9, and the support frame 43 is fixed to the upper and lower protection zones 4 and 9 where the inner close-fitting heat insulating layer 41 is arranged. Wherein, braced frame 43 is preferably the modularized design, is convenient for on-spot lift by crane and quick installation to braced frame is formed by the shaped steel concatenation, including horizontal brace, vertical brace and bracing etc..
The outer protective layer 42 is made of a protective layer resistant to high temperature radiation and rain and snow erosion and having a high reflectivity on the surface, so as to effectively insulate and protect the heat absorber. The thickness of the outer protective layer 42 is related to the temperature of the outer wall, and is preferably a double-layer or multi-layer structure, so that the maintenance or replacement of the outer vulnerable area part is facilitated, and the replacement cost can be reduced; and, adjacent layers are installed in a staggered seam pressed structure, as shown in fig. 3, to prevent sunlight from penetrating through the gap and irradiating the back system or structure.
According to the utility model discloses, the outmost a plurality of counter bore that is provided with of outer inoxidizing coating 42, outer inoxidizing coating 42 is fixed on braced frame 43 through the fixing bolt 423 that passes the counter bore. In order to prevent the fixing bolt 423 from being directly exposed to sunlight, after the nut and the washer are mounted, a sealing filler is filled in the counterbore in which the fixing bolt is mounted, wherein the material of the sealing filler is preferably the same as that of the outer protective layer 42.
As shown in fig. 1, the lower part of the lower protection zone 9 is uniformly provided with openable or closable ventilation inlets 7 along the circumferential direction, and the ventilation inlets 7 can also be used as an access of an overhaul platform of the heat absorption tower 1; the top of the heat absorber is provided with a ventilation outlet, so that the air can be promoted to flow in the heat absorber by utilizing high-altitude natural convection and temperature pressure.
The ventilation inlet 7 can be opened or closed in a targeted manner according to the daily or hourly wind direction of the project, and the internal electrical and thermal control system or equipment of the heat absorber is maintained to work within the safety allowable working temperature requirement through air flow.
The present invention will be described with reference to the following embodiments.
As shown in fig. 1, the heat absorber system is arranged on a heat absorption tower 1, an internal supporting steel structure 3 is fixed on a heat absorption tower platform 2, a heat absorption tube panel is hung on the outer side of the heat absorber, an effective heating area 5 is formed, the heat absorber directly bears solar radiation to the light side for heat absorption, and a back heat insulation layer 6 is laid on the backlight for ensuring the heat efficiency of the heat absorber.
The upper and lower regions of the heated tube panel are respectively an upper protection region and a lower protection region, and the high-temperature heat-insulation protection structure adopts an inner and outer double-layer structure design. As shown in fig. 2, the outer protective layer 42 is made of a protective plate with high temperature radiation resistance, rain and snow erosion resistance, high surface reflectivity and the like, and the outer protective layer 42 is fixed on the supporting frame 43 to insulate and protect the heat absorber; the inner layer is an inner close-fitting closed heat-insulating layer 41 made of conventional heat-insulating materials for maintaining the temperature of the heat absorber, and an air layer is arranged between the inner close-fitting closed heat-insulating layer 41 and the outer protective layer 42.
As shown in fig. 3, the outer protection layer 42 has a double-layer or multi-layer structure, such as a first protection plate inner layer 4211 and a first protection plate outer layer 4221 or a second protection plate inner layer 4212 and a second protection plate outer layer 4222, wherein the inner layer and the outer layer are installed in a staggered seam pressing structure to prevent sunlight from irradiating the back structure or system through the gap. The outer layer of the outer protective layer 42 is designed and processed with a counter bore, and is fixed on the supporting frame 43 through the fixing bolt 423, and the counter bore is filled with a sealing filler after being screwed down by a nut, so that the fixing bolt 423 is prevented from being directly exposed to sunlight irradiation. Wherein, the sealing filler material is the same as the material of the outer protective layer.
The lower part of the lower protection area 9 is annularly and uniformly provided with ventilation inlets 7 which are also used as an inlet and an outlet of the heat absorption tower platform 2; a ventilation outlet 8 is arranged at the top of the absorber. The ventilation inlet 7 is opened or closed in a targeted manner according to the local daily or hourly wind direction of the project, and the natural convection or forced convection at high altitude and the temperature pressure are utilized to promote the atmosphere to flow in the interior of the heat absorber, so as to maintain the electrical and thermal control system or equipment in the interior of the heat absorber within the requirement of safe allowable working temperature.
To sum up, the utility model provides a new high-temperature thermal insulation protection structure for tower type photo-thermal power station heat absorber, which separates the thermal insulation protection and the thermal insulation function of the heat absorber, the outer layer adopts the protection plate with the characteristics of high temperature radiation resistance, rain and snow erosion resistance and higher reflectivity on the surface to carry out thermal insulation protection on the heat absorber, and the inner layer adopts the close-fitting closed thermal insulation layer made of the conventional thermal insulation material to carry out thermal insulation and temperature maintenance on the heat absorber; in addition, reasonable and sufficient ventilation inlets and outlets are considered in structural design so as to ensure that when the heat absorber runs at high temperature in summer, internal electrical and thermal control systems or equipment are maintained within the requirement of safe allowable working temperature, and meanwhile, the ventilation inlets can be opened or closed in a targeted manner according to the local daily or hourly wind direction of a project.
The present invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification, and to any novel method or process steps or any novel combination of features disclosed.

Claims (9)

1. The utility model provides a tower light and heat power station heat absorber is with thermal-insulated protective structure of high temperature which characterized in that, thermal-insulated protective structure of high temperature includes braced frame and sets up respectively the inboard close-fitting heat preservation of interior of braced frame and the outer inoxidizing coating in the outside are sealed, close-fitting heat preservation of interior and outer inoxidizing coating between be the air bed.
2. The high-temperature thermal insulation protection structure for the tower-type solar-thermal power station heat absorber as claimed in claim 1, wherein the high-temperature thermal insulation protection structure is arranged in an upper protection zone and a lower protection zone of an effective heating zone of the tower-type solar-thermal power station heat absorber.
3. The high-temperature thermal insulation protective structure for the tower-type solar thermal power station heat absorber as claimed in claim 2, wherein the inner close-fitting heat insulation layer is fixed on the inner supporting steel structure of the upper protective zone and the lower protective zone.
4. The high-temperature thermal insulation protective structure for the tower-type solar-thermal power station heat absorber as claimed in any one of claims 1 to 3, wherein the outer protective layer is a protective plate which is resistant to high-temperature radiation, rain and snow scouring and has high reflectivity on the surface.
5. The high temperature thermal protection structure for the tower photo-thermal power station heat absorber of claim 1, wherein the back side of the outer protection layer is fixed on a support frame, and the support frame is of a modular structural design.
6. The high-temperature thermal insulation protective structure for the tower type solar-thermal power station heat absorber as claimed in any one of claims 1 to 3, wherein the outer protective layer is of a double-layer or multi-layer structure, and adjacent layers are installed in a staggered seam pressing structure.
7. The high-temperature heat insulation protection structure for the tower type photothermal power station heat absorber as claimed in claim 6, wherein a plurality of counter bores are formed in the outermost layer of the outer protection layer, and the outer protection layer is fixed on the support frame through fixing bolts penetrating through the counter bores.
8. The high-temperature heat insulation protection structure for the tower type solar-thermal power station heat absorber as claimed in claim 7, wherein the counter bore provided with the fixing bolt is filled with a sealing filler.
9. The high-temperature thermal insulation protection structure for the tower type solar-thermal power station heat absorber as claimed in claim 2, wherein the lower part of the lower protection area is uniformly provided with openable or closable ventilation inlets along the circumferential direction, and the top of the heat absorber is provided with a ventilation outlet.
CN201920328980.6U 2019-03-15 2019-03-15 High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber Active CN209944783U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201920328980.6U CN209944783U (en) 2019-03-15 2019-03-15 High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201920328980.6U CN209944783U (en) 2019-03-15 2019-03-15 High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber

Publications (1)

Publication Number Publication Date
CN209944783U true CN209944783U (en) 2020-01-14

Family

ID=69124066

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201920328980.6U Active CN209944783U (en) 2019-03-15 2019-03-15 High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber

Country Status (1)

Country Link
CN (1) CN209944783U (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109899997A (en) * 2019-03-15 2019-06-18 东方电气集团东方锅炉股份有限公司 A kind of tower photo-thermal power station heat dump high temperature insulating safeguard structure

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109899997A (en) * 2019-03-15 2019-06-18 东方电气集团东方锅炉股份有限公司 A kind of tower photo-thermal power station heat dump high temperature insulating safeguard structure

Similar Documents

Publication Publication Date Title
CN107380780B (en) Double-layer jacket high-temperature molten salt storage tank
WO2017008714A1 (en) Heat dissipation retaining structure for heat production device, installation method thereof, and wind turbine generator set
CN104412047A (en) Insulating glass style solar heat collector and building using solar energy for heating and cooling employing same
AU2004288010A1 (en) Solar tiles
CN100575811C (en) Solar energy power generating-water heater compound assembly and system
CN109617509B (en) Phase-change heat-storage solar photovoltaic photo-thermal flat plate collector
CN201839236U (en) Solar electric heating composite component and electric heating composite system
CN209944783U (en) High-temperature heat insulation protection structure for tower type photo-thermal power station heat absorber
CN208794756U (en) A kind of solar water heater cyclic water tank
CN108365793B (en) Thermoelectric power generation device utilizing solar photovoltaic power generation waste heat and wind power for heating
CN108548336B (en) Windproof device for tower-type solar heat absorber
CN216342607U (en) Novel heat collection type hot air flow power generation system
CN207226152U (en) A kind of double-jacket salt storage tank
CN109899997A (en) A kind of tower photo-thermal power station heat dump high temperature insulating safeguard structure
CN205336223U (en) Photovoltaic light and heat integration photoelectricity heater with high temperature self -protection mechanism
CN202734262U (en) Wall-mounted-type optical-wave heating dual-layer-container solar water heater
CN102705940A (en) All-weather floor heating and cooling system
CN107152798A (en) It is a kind of to be provided with the solar thermal collector for exempting to weld fin
CN207214482U (en) A kind of tower surface heat dump tube panel of vacuum heat-preserving
CN201811455U (en) Double-lighting sunning type solar water heater
CN102052776B (en) Solar heat collection device with hood glass tube heat-release vacuum circulating heat collection element
CN101442281B (en) Method and apparatus for using solar through photoelectric photo-thermal homobody synchronous transition
CN111817657A (en) Solar photovoltaic panel assembly with snow melting function
CN206683253U (en) Effectively reduce the device of groove type solar vacuum heat-collecting mirror field thermal radiation loss
CN205807865U (en) The warming solar energy case of extremely frigid zones outdoor electrical equipment

Legal Events

Date Code Title Description
GR01 Patent grant
GR01 Patent grant