Intelligent and rapid heating device for microwave water jacket of hydraulic oil station of coal mill of thermal power plant

Abstract

The application discloses a kind of coal mill hydraulic oil station microwave water jacket intelligent rapid heating device of thermal power plant, including hydraulic oil tank body, microwave heating assembly, temperature detection component and control unit, sleeve cover cavity is set on the outer wall of hydraulic oil tank body, the metal wall surface of cavity cover body has to face hydraulic oil tank body, heat exchange medium is filled in cavity cover body, microwave heating assembly is arranged on cavity cover body, heat is indirectly conducted to the inside of hydraulic oil tank body by metal wall surface, temperature detection component includes oil temperature sensor and water temperature sensor, control unit is signal connected with oil temperature sensor and water temperature sensor, control unit is electrically connected with microwave heating assembly.The coal mill hydraulic oil station microwave water jacket intelligent rapid heating device of thermal power plant provided by the present application is convenient for low-temperature start of hydraulic oil station, non-contact indirect heating is warmed up quickly and safely, and is convenient for automatic control.

Description

Technical Field

[0001] This invention relates to the field of coal mill technology, and in particular to an intelligent rapid heating device for microwave water jacket of hydraulic oil station in coal mill of thermal power plant. Background Technology

[0002] The coal mill is a crucial auxiliary machine in thermal power plants and the core of the pulverizing system. Hydraulic oil is the power transmission medium for the coal mill. In thermal power plants located at high latitudes and altitudes, where the unit is shut down for extended periods or during winter when ambient temperatures are low, the oil temperature often falls below the allowable starting value for the hydraulic oil pump (below 15°C). This causes the hydraulic oil to become viscous, preventing the pump from restarting after a shutdown, thus limiting the start-up conditions of the coal mill. Traditional immersion-type electric heating elements, which directly contact the oil, are prone to oxidation, carbonization, coking, corrosion, leakage, and contamination. Furthermore, they suffer from low temperature control accuracy and insufficient automation. Summary of the Invention

[0003] This invention is based on the inventor's discoveries and understanding of the following facts and problems: Direct heating of hydraulic oil is ineffective. The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a microwave water jacket intelligent rapid heating device for a hydraulic oil station of a coal mill in a thermal power plant, comprising a hydraulic oil tank body, a microwave heating component, a temperature detection component, and a control unit. The hydraulic oil tank body is used to contain hydraulic oil, and a jacket cavity is fitted on the outer wall of the hydraulic oil tank body. The jacket cavity has a metal wall facing the hydraulic oil tank body, and the jacket cavity is filled with a heat exchange medium. The microwave heating component is arranged on the jacket cavity to microwave heat the heat exchange medium in the jacket cavity. The heat is indirectly conducted to the hydraulic oil tank body through the metal wall. The temperature detection component includes an oil temperature sensor and a water temperature sensor. The oil temperature sensor is used to monitor the oil temperature in the hydraulic oil tank body, and the water temperature sensor is used to monitor the temperature in the jacket cavity. The control unit is signal-connected to the oil temperature sensor and the water temperature sensor, and is electrically connected to the microwave heating component. The control unit controls the start / stop and output power of the microwave heating component according to the input oil temperature signal and water temperature signal.

[0005] The microwave water jacket intelligent rapid heating device for hydraulic oil stations of coal mills in thermal power plants, according to embodiments of the present invention, facilitates low-temperature start-up of hydraulic oil stations, provides rapid temperature rise through non-contact indirect heating, ensures good safety, and is easy to automate.

[0006] In some embodiments, a circulation mechanism is further included, comprising a circulating water pump and inlet / outlet pipes. The inlet / outlet pipes are respectively connected to the inlet and outlet of the circulating water pump to form a circulation loop. The circulation loop is connected to the jacket cavity, and the circulating water pump is electrically connected to the control unit. The circulating water pump is used to provide circulation power.

[0007] In some embodiments, a central water storage and heat storage tank is also included, which is connected in parallel with multiple independent jacketed cavities through pipelines to form a heat exchange network.

[0008] In some embodiments, a flow guiding structure is provided in the jacket cavity to guide the water flow in the jacket cavity along a preset path.

[0009] In some embodiments, the microwave heating assembly includes a magnetron and a waveguide connected to the magnetron, the waveguide emitting microwaves oriented toward the jacket cavity, and the waveguide being electrically connected to the control unit.

[0010] In some embodiments, the magnetron transmits at a frequency of 2450 MHz.

[0011] In some embodiments, the jacket cavity is provided with a water inlet, a drain outlet, and a seal, the seal being used to seal the water inlet and the drain outlet.

[0012] In some embodiments, the heat exchange medium filled in the jacket cavity is deionized water.

[0013] In some embodiments, the control unit controls the microwave heating component based on the oil temperature T1 monitored by the oil temperature sensor. When T1 is less than a first preset temperature, the microwave heating component is started; when T1 is less than a second preset temperature, the microwave heating component is stopped. The control unit controls the output power of the microwave heating component based on the water temperature T2 monitored by the water temperature sensor. When T2 reaches a third preset temperature, the output power of the microwave heating component is adjusted to maintain the water temperature at the third preset temperature.

[0014] In some embodiments, the first preset temperature is 15°C, the second preset temperature is 50°C, and the third preset temperature is 80°C.

[0015] This application offers the following advantages: Microwave heating components, combined with oil temperature sensors, water temperature sensors, and control units, achieve non-contact indirect heating, preventing oil oxidation, carbonization, and coking, thus improving safety and automation. A circulating water pump and inlet / outlet pipes form a circulation loop, accelerating convective heat transfer in the water medium, ensuring uniform water temperature distribution within the jacketed cavity, and shortening heating time. A central water storage tank and multiple jacketed cavities connected in parallel form a heat exchange network, enabling multiple oil stations to share a heat source, reducing overall installed energy consumption. A flow guiding structure directs water flow along a preset path to flush the metal wall, eliminating flow dead zones and improving the lateral convective heat transfer coefficient. A magnetron and waveguides oriented towards the jacketed cavity concentrate microwave energy within the water, improving energy utilization and preventing microwave leakage. The magnetron's emission frequency matches the dipole relaxation frequency of water molecules, ensuring both penetration depth and heating uniformity. A water inlet, drain outlet, and corresponding seals allow for regular water replacement and impurity discharge, maintaining the low conductivity characteristics of deionized water. The jacket cavity is filled with deionized water to prevent electrochemical corrosion caused by ions in the microwave field and to prevent scale buildup. The strategy of controlling the start and stop based on oil temperature T1 and controlling the power based on water temperature T2 ensures that the water temperature stabilizes before the constant temperature point, and the oil temperature rises smoothly to the stop threshold under constant heat flow without overshoot. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the microwave water jacket intelligent rapid heating device for the hydraulic oil station of a coal mill in a thermal power plant, according to an embodiment of the present invention.

[0017] Reference numerals: 1. Hydraulic oil tank body; 2. Microwave heating assembly; 3. Jacket cavity; 4. Temperature detection assembly; 41. Water temperature sensor; 42. Oil temperature sensor; 5. Control unit; 6. Circulating water pump; 7. Central water storage and heat storage tank. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] This invention provides an intelligent rapid heating device for a microwave water jacket in a coal mill hydraulic oil station of a thermal power plant. The device includes a hydraulic oil tank body 1, a microwave heating component 2, a temperature detection component 4, and a control unit 5. The hydraulic oil tank body 1 contains hydraulic oil. A jacket cavity 3 is fitted onto the outer wall of the hydraulic oil tank body 1. The jacket cavity 3 has a metal wall facing the hydraulic oil tank body 1. The jacket cavity 3 is filled with a heat exchange medium. The microwave heating component 2 is arranged on the jacket cavity 3 to microwave heat the heat exchange medium within the jacket cavity 3. Heat is indirectly conducted to the hydraulic oil tank body 1 through the metal wall. The temperature detection component 4 includes an oil temperature sensor 42 and a water temperature sensor 41. The oil temperature sensor 42 monitors the oil temperature inside the hydraulic oil tank body 1, and the water temperature sensor 41 monitors the temperature inside the jacket cavity 3. The control unit 5 is signal-connected to the oil temperature sensor 42 and the water temperature sensor 41, and is electrically connected to the microwave heating component 2. The control unit 5 controls the start / stop and output power of the microwave heating component 2 based on the input oil temperature and water temperature signals.

[0020] Specifically, the hydraulic oil tank body 1 serves as the final recipient of heat from the heating device. The hydraulic oil tank body 1 contains the hydraulic oil required by the coal mill's hydraulic system, and heating is performed when the oil becomes viscous at low temperatures. The jacketed cavity 3, fitted onto the outer wall of the hydraulic oil tank body 1, has a metal wall facing the hydraulic oil tank body 1. The jacketed cavity 3 contains a heat exchange medium, which can be water. Utilizing the excellent thermal conductivity of the metal wall, the heat generated after microwave heating of the water medium is transferred to the hydraulic oil tank body 1 through heat conduction and convection, achieving non-contact indirect heating.

[0021] Microwave heating is faster than traditional resistance heating because microwave energy acts directly on the water rather than being conducted through a heating element, resulting in high thermal efficiency. An oil temperature sensor 42 is located in the hydraulic oil tank body 1 to monitor oil temperature, and a water temperature sensor 41 is located in the jacket cavity 3 to monitor water temperature. Both sensors provide real-time temperature signals to the control unit 5, forming the temperature sensing capability of the control unit 5. The control unit 5 is connected to both types of temperature sensors and electrically connected to the microwave heating assembly 2. Based on the input oil and water temperature signals, it controls the start / stop and output power of the microwave heating assembly 2. The combined operation of the oil temperature sensor 42 and the water temperature sensor 41 allows the control unit 5 to simultaneously acquire the temperature status of both the heated object (hydraulic oil) and the heat exchange medium (water), avoiding control lag or overshoot caused by single-point monitoring. The water temperature sensor 41 detects water temperature changes in advance, allowing the control unit 5 to pre-adjust the heating power before the oil temperature reaches the target value. The constant water temperature control strategy ensures stable heat output. The oil temperature sensor 42 serves as the final control target, providing the basis for determining heating termination. The two sensors work together for control. The control unit 5 adjusts the power based on the water temperature signal instead of simply starting and stopping it, avoiding the adverse effects of frequent starting and stopping of the microwave heating component 2 on the power grid and equipment lifespan. At the same time, it maintains a constant water temperature to ensure a stable heat source temperature, so that the hydraulic oil receives a continuous and uniform heat input.

[0022] The microwave heating component 2 is installed at a suitable location on the outside or inside of the jacketed cavity 3, with the microwave output end facing the water inside the jacketed cavity 3. This ensures that the microwave energy acts directly on the water rather than penetrating the metal wall to heat the hydraulic oil. Utilizing the excellent microwave absorption characteristics of water, the microwave energy is efficiently converted into heat energy. The jacketed cavity 3 is sealed and covers the outer wall of the hydraulic oil tank. The jacketed cavity 3 can be made of stainless steel, which is corrosion-resistant, has good thermal conductivity, and will not rust or leak even after long-term contact with deionized water, ensuring reliable long-term operation of the equipment. The entire device does not require modification of the original oil circuit, pump body, or oil tank body, facilitating on-site installation and modification, and is adaptable to hydraulic oil tanks of different volumes.

[0023] Microwave indirect heating avoids direct contact between the heating element and hydraulic oil, eliminating the problems of oil oxidation, carbonization, coking, corrosion, and leakage caused by traditional immersion electric heating tubes. The combination of microwave heating and a jacketed water medium separates the heat generation and heat dissipation points. Microwave energy is generated in the water and conducted to the hydraulic oil through the metal walls, eliminating the risk of oil contamination and electrical short circuits caused by corrosion and rupture of electric heating tubes. This enables fully unattended automated operation, reducing the workload of operators and avoiding potential misjudgments and errors that may occur with manual operation.

[0024] In some embodiments, a circulation mechanism is also included, comprising a circulating water pump 6 and inlet and outlet pipes. The inlet and outlet pipes are respectively connected to the inlet and outlet of the circulating water pump 6 to form a circulation loop. The circulation loop is connected to the jacket cavity 3, and the circulating water pump 6 is electrically connected to the control unit 5. The circulating water pump 6 is used to provide circulation power.

[0025] Specifically, the circulation loop is connected to the water-containing space of the jacketed cavity 3, allowing water to flow continuously between the cavity and the pipeline. The circulating water pump 6 is electrically connected to the control unit 5 and receives start / stop commands from the control unit 5 to provide circulation power. The circulating water pump 6 drives deionized water to flow within the jacketed cavity 3 using forced convection. Valves can be installed on the inlet and outlet pipelines. A supply valve and a return valve are installed on both sides of the circulating water pump 6 to control the inflow and outflow rates. The two valves work together to achieve variable flow operation of the circulating water pump 6 at a constant speed, avoiding motor frequency conversion losses and electromagnetic interference caused by frequent speed adjustments of the circulating water pump 6. When the circulating water pump 6 is under maintenance or malfunctions, closing the supply and return valves can isolate the circulating water pump 6 from the water system, enabling online disassembly without draining the water from the jacketed cavity 3.

[0026] When the microwave heating component 2 is started, the control unit 5 simultaneously starts the circulating water pump 6, forcing water to flush the metal wall facing the hydraulic oil tank body 1. This breaks up the uneven heat distribution that may be caused by microwave radiation, preventing the water temperature near the microwave source from being too high while the water temperature near the metal wall is too low, thus making the water temperature in the jacket cavity 3 more uniform. Without the forced convection of the circulation mechanism, the water near the metal wall cools down due to continuous heat transfer to the hydraulic oil, while the water near the microwave source continuously absorbs microwave energy and heats up. The temperature difference between the two gradually widens over time, which may lead to the failure of constant water temperature control, or even the water temperature near the wall falling below the set value while the water in the microwave radiation area is close to the boiling point.

[0027] After the water temperature is homogenized, the temperature value collected by the water temperature sensor 41 can accurately reflect the overall thermal state of the water body, thus achieving precise temperature control. The inlet and outlet pipes are arranged on opposite sides of the jacketed cavity 3, for example, with an inlet at the bottom of one side and an outlet at the top of the other, creating a continuous convection path along the longitudinal direction of the cavity. The water flow direction is consistent with the natural convection direction, reducing flow resistance and preventing water stagnation. The control unit 5 can also adjust the operating status of the circulating water pump 6 according to the different operating stages: maintaining full speed during the rapid heating stage to maximize heat exchange efficiency, and reducing the pump speed after the water temperature enters the constant temperature range to reduce heat exchange loss between the water body and the external environment, achieving energy saving. After the circulating water pump 6 is electrically connected to the control unit 5, the control unit 5 can also simultaneously stop the circulating water pump 6 when the water shortage protection or over-temperature protection is activated, preventing the pump from running dry and damaging the mechanical seal. The circulation mechanism does not alter the original oil circuit, pump body, and oil tank body, and is compatible with the sealing structure of the jacket cavity 3. The inlet and outlet pipelines are connected to the jacket cavity 3 through sealing joints to ensure that the water cavity is sealed and leak-free. The circulating water pump 6 accelerates the water flow, increasing the heat transferred from the water medium to the hydraulic oil tank body 1 per unit time, shortening the time required for the hydraulic oil to rise from a low temperature to the allowable starting value, and meeting the rapid cold start requirements of the coal mill.

[0028] In some embodiments, the oil temperature sensor 42 and the temperature sensor are integrated on the DCS integrated block, and the control unit 5 is a PLC control cabinet. The PLC control cabinet automatically protects the equipment when it detects overheating, water shortage, or abnormalities. The detection probes of the oil temperature sensor 42 and the temperature sensor are respectively arranged on the hydraulic oil tank body 1 and the jacket cavity 3. The DCS integrated block, as a local signal acquisition and preprocessing unit, converts the analog signals output by the two sensors into standard digital signals after isolation amplification, analog-to-digital conversion, and linearization correction, and then transmits them to the PLC control cabinet, which serves as the control unit 5. In this way, the PLC control cabinet can be placed in a safe environment to reduce the influence of distance on the signal. The two temperature signals are acquired synchronously within the DCS integrated block to ensure that the oil temperature and water temperature received by the PLC control cabinet have the same time base. The DCS integrated block can also reserve a signal output channel to upload the operating status, real-time temperature, and alarm information of the heating device to the operator station in the power plant's central control room, realizing the functions of remote monitoring and centralized control.

[0029] In some embodiments, a central water storage and heat storage tank is also included, which is connected in parallel with multiple independent jacketed cavities 3 through pipelines to form a heat exchange network.

[0030] Specifically, thermal power plants often consist of multiple pulverizing systems, and the hydraulic oil stations for coal mills are also designed with multiple units. A central water storage and heat storage tank can save energy and reduce consumption. As a heat storage tank for the entire heat exchange network, the central water storage and heat storage tank is filled with deionized water as the heat storage medium. Utilizing the high specific heat capacity of water, it buffers the heat fluctuations between the instantaneous output of the microwave heating component 2 and the terminal load, allowing the microwave heating component 2 to operate continuously in a high-efficiency power range without frequent start-stop cycles following the load changes of individual oil stations. The parallel connection method ensures that each jacketed cavity 3 is independent in terms of pipeline pressure drop. Flow regulation in any branch of a jacketed cavity 3 does not cause sudden changes in flow in other branches. Each branch independently obtains hot water from the central water storage and heat storage tank and independently returns water to the tank.

[0031] The central water storage and heat storage tank, together with the circulating water pump 6, forms a two-stage circulation architecture. The main circulating water pump 6 drives the hot water in the heat storage tank to flow through the main pipes of each branch. Each branch of the jacketed cavity 3 is equipped with a branch electric regulating valve. The control unit 5 independently adjusts the hot water flow of the branch according to the signals of the corresponding oil temperature sensor 42 and water temperature sensor 41, so as to realize the distribution of heat on demand. When the oil temperature of a coal mill is lower than 15°C and heating is required, the central water storage and heat storage tank can immediately supply preheated hot water to the branch at close to 80°C, shortening the waiting time for a single cold start. At the same time, when multiple coal mills need to be heated at the same time, the heat storage tank can buffer the instantaneous heating peak of the microwave heating component 2 with its heat storage capacity, reducing the demand on the total installed power of the microwave heating component 2. The parallel heat exchange network also allows for the isolation, maintenance, water replenishment, and sewage discharge of a single jacketed cavity 3 without affecting the normal operation of other branches and the central water storage and heat storage tank, thus improving the system availability.

[0032] The control unit 5 can connect to the status signals of each branch via a communication interface to centrally manage the water level and temperature of the thermal storage tank and the operating parameters of all branches, and to coordinate the start / stop and power output of the microwave heating component 2, thus avoiding grid impact caused by load superposition when each oil station heats independently. The central water storage thermal storage tank's main water supply pipe exits from the bottom of the tank, is pressurized by the main circulating water pump 6, and then distributed to the inlet electric valves of each branch. The water inlet of each branch passes through the corresponding jacket cavity 3 and then flows into the return water main pipe at the top of the tank via the return water branch. The higher temperature return water enters the upper hot layer of the tank, while the lower temperature supply water is drawn from the lower cold layer of the tank, maintaining a stable temperature gradient inside the thermal storage tank and improving the utilization rate of the heat source.

[0033] The central water storage and heat storage tank can be connected in series on the inlet and outlet pipes of the circulation mechanism. The top of the central water storage and heat storage tank is equipped with an outlet and a water inlet, and the bottom of the central water storage and heat storage tank is equipped with an inlet. The inlet receives water from the circulating water pump 6 and flows back to the jacket cavity 3 through the outlet. The water inlet is arranged on the central water storage and heat storage tank for easy control, which can simplify the structure of the jacket cavity 3 and reduce the risk of leakage.

[0034] In some embodiments, a flow guiding structure is provided inside the jacket cavity 3 to guide the water flow inside the jacket cavity 3 along a preset path.

[0035] Specifically, the flow guiding structure, acting as a physical barrier or flow channel guide, directs the water flow within the jacket cavity 3 along a predetermined path, allowing the water to sequentially flush the metal walls facing the hydraulic tank body 1 in the designed direction. The flow guiding structure can be a spiral guide plate or a longitudinal baffle. When using a spiral guide plate, the water flows spirally upwards along the outer wall of the hydraulic tank, increasing the contact distance and contact time between the water and the metal wall. When using a longitudinal baffle, the water flows back and forth along the length of the tank, forming an S-shaped or serpentine flow channel, eliminating dead zones within the jacket cavity 3. The flow guiding structure transforms the flow state within the jacket cavity 3 from disordered natural convection or random turbulence into a controlled forced convection distribution, avoiding the temperature difference where the water temperature rises rapidly in the microwave radiation area and slowly in areas far from the radiation area, thus ensuring a more uniform water temperature across all areas of the jacket cavity 3.

[0036] The guide plate can be perpendicular to the heat transfer direction or at a certain angle to it, forcing water to scour the metal wall facing the hydraulic tank body 1. This disrupts the high-temperature gradient boundary layer formed by continuous heat conduction at the wall, reducing thermal resistance and increasing the convective heat transfer coefficient from the water medium to the metal wall. The guide structure is made of the same stainless steel as the jacket cavity 3 and is fixed to the inner wall of the jacket cavity 3 by welding or riveting. An appropriate gap is maintained between the end of the guide plate and the opposite wall to balance the flow resistance of each channel and avoid excessive local flow velocity that could cause a sudden increase in pump load. Turbulence protrusions or openings can be set on the preset path to generate local micro-turbulence in the boundary layer water, enhancing the heat transfer effect at the wall.

[0037] In some embodiments, the microwave heating assembly 2 includes a magnetron and a waveguide connected to the magnetron. The waveguide emits microwaves oriented toward the jacket cavity 3, and the magnetron is electrically connected to the control unit 5.

[0038] Specifically, the magnetron acts as a microwave source, converting electrical energy into industrial microwave energy. A waveguide is connected to the magnetron's output, serving as a microwave transmission channel. The waveguide's end is oriented towards the jacket cavity 3, confining and guiding the microwave energy generated by the magnetron to the deionized water within the jacket cavity 3. This allows the microwave energy to act directly on the water rather than being scattered to the external environment or metal walls, resulting in rapid heating of the water molecules through polar vibrations.

[0039] Directional emission ensures that microwave energy is concentrated on the water body, preventing microwave leakage to the metal walls of the tank and causing reflection loss. Direct microwave heating of the water results in a faster temperature rise than traditional resistance heating. The magnetron is electrically connected to the control unit 5 via a power supply. The control unit 5 can adjust the magnetron anode current in real time based on the signal from the water temperature sensor 41 to change the output power. After the magnetron generates microwaves, they are reflected multiple times by the inner wall of the waveguide and propagate along the transmission direction. The cross-sectional dimensions of the waveguide are matched to the microwave wavelength to ensure that the microwaves are transmitted in the dominant mode, reducing energy attenuation caused by higher-order modes.

[0040] In some embodiments, the magnetron transmits at a frequency of 2450 MHz.

[0041] Specifically, the magnetron's transmission frequency is set to 2450MHz, which matches the inherent frequency of deionized water molecules. This causes the water molecules to generate strong polar vibrations and directional polarization under the action of the alternating electric field at this frequency, maximizing the conversion of microwave energy into molecular thermal kinetic energy. The selection of the frequency takes into account both heating efficiency and safety. Below this frequency, the dipole orientation of water molecules cannot keep up with the change in electric field, resulting in a decrease in polarization loss. Above this frequency, the microwave penetration depth decreases sharply, causing heating to concentrate on the surface of the water. 2450MHz is in the moderate loss region of the microwave absorption spectrum of the water medium, balancing heating uniformity and energy conversion efficiency, so that the overall temperature rise rate of deionized water in the jacket cavity 3 reaches the optimal level.

[0042] The 2450MHz microwave penetrates water to a depth of several centimeters, matching the thickness of the water channel in the flow guide structure, ensuring that each layer of water effectively absorbs microwave energy as it flows through the microwave irradiation area. When the control unit 5 adjusts the magnetron output power, the fixed 2450MHz frequency does not shift due to power changes, guaranteeing consistent coupling efficiency between the microwave and water at different power levels.

[0043] In some embodiments, the jacket cavity 3 is provided with a water inlet, a drain outlet, and a seal, the seal being used to seal the water inlet and the drain outlet.

[0044] Specifically, the water inlet serves as an external deionized water injection channel. When the water volume decreases due to evaporation or minor leakage after initial filling or long-term operation, deionized water is replenished to the preset water level in the jacket cavity 3 through the water inlet to maintain the water medium filling volume sufficient for microwave absorption and heat transfer. The drain outlet is used to discharge trace impurities, suspended solids, or trace oxides generated from contact with the metal wall that may accumulate after long-term circulation. It can also be used to drain all water from the cavity during equipment maintenance or shutdown for antifreeze purposes. Seals are installed at the interfaces of the water inlet and drain outlet to close these two openings when not in operation. The water inlet is located above the highest water level line of the jacket cavity 3, allowing water to be replenished by gravity flow. The drain outlet is located at the lowest point of the jacket cavity 3 to ensure that sediments within the cavity are completely carried away by the water flow during drainage.

[0045] The sealing element can be a combination of a heat-resistant rubber gasket and a threaded gland to reliably seal the opening after water replenishment and drainage operations. First, open the drain outlet to discharge old water and bottom sediment, then inject fresh deionized water into the water inlet until clear water flows out of the drain outlet. Then close the drain outlet and continue replenishing to the standard water level before closing the water inlet seal.

[0046] A water level sensor or observation mirror can be installed near the water inlet. The water level sensor is connected to the control unit 5. When the water level is detected to be lower than the preset lower limit, the control unit 5 will prevent the microwave heating component 2 from starting or automatically stop the ongoing heating. The combination of the water inlet, drain outlet and seals makes water level maintenance highly operable. Operators can regularly check and adjust the water level through the water inlet and replace all the water through the drain outlet according to the maintenance cycle to maintain the purity of the water medium and extend the service life of the equipment.

[0047] In some embodiments, the heat exchange medium filled in the jacket cavity 3 is deionized water.

[0048] Specifically, the heat exchange medium filled in the jacket cavity 3 is deionized water, which serves as both a microwave energy absorber and a heat transfer carrier. After treatment to remove calcium, magnesium, and chloride ions, the deionized water has low conductivity, preventing ions in the water from forming conductive pathways under the influence of a 2450MHz microwave electric field, thus avoiding stray currents or electrochemical corrosion. This ensures that all microwave energy is used for heat generation through the dipole polarization vibration of water molecules rather than being lost in ion migration and conductivity. Compared to ordinary tap water, this method offers higher heating efficiency and produces no electrolytic byproducts.

[0049] Deionized water possesses strong thermal buffering capacity within a constant temperature range of 80℃. When the power of the microwave heating component 2 fluctuates briefly, the water temperature changes at a gradual rate, facilitating the maintenance of a constant water temperature at the set value. During heating, deionized water does not precipitate solid deposits or colloidal substances, preventing the formation of scale on the metal wall surface after long-term operation, which would increase thermal resistance. This ensures that the metal wall facing the hydraulic oil tank body 1 remains clean and thermally conductive, efficiently transferring heat to the hydraulic oil. Simultaneously, the absence of scale buildup prevents uneven thermal stress on the metal wall surface caused by localized overheating, extending the service life of the jacket cavity 3.

[0050] In some embodiments, the control unit 5 controls the microwave heating component 2 according to the oil temperature T1 monitored by the oil temperature sensor 42. When T1 is less than the first preset temperature, the microwave heating component 2 is started; when T1 is less than the second preset temperature, the microwave heating component 2 is stopped. The control unit 5 controls the output power of the microwave heating component 2 according to the water temperature T2 monitored by the water temperature sensor 41. When T2 reaches the third preset temperature, the output power of the microwave heating component 2 is adjusted to maintain the water temperature at the third preset temperature.

[0051] Specifically, the control unit 5 executes the start / stop decision of the microwave heating component 2 based on the oil temperature T1 monitored by the oil temperature sensor 42: when T1 is lower than the first preset temperature, the microwave heating component 2 is started; when T1 reaches the second preset temperature, the microwave heating component 2 is stopped. Simultaneously, the control unit 5 continuously adjusts the output power of the microwave heating component 2 based on the water temperature T2 monitored by the water temperature sensor 41: when T2 reaches the third preset temperature, the output power of the microwave heating component 2 is adjusted to maintain the water temperature constant at the third preset temperature. The first preset temperature corresponds to a start threshold of 15℃, the second preset temperature corresponds to a stop threshold of 50℃, and the third preset temperature corresponds to a constant temperature setpoint of 80℃. The oil temperature T1, as the final controlled object, determines the start and termination of the heating process, while the water temperature T2, as an intermediate process variable, serves as the basis for power adjustment.

[0052] The control unit 5 uses oil temperature as the target to determine whether heating should proceed, and water temperature as the regulating factor to maintain a stable heat source temperature. The two work together to ensure the oil temperature rises smoothly from below 15℃ to 50℃ without overshoot or heating interruption. When the water temperature T2 reaches the third preset temperature, the control unit 5 does not stop heating but switches to power regulation mode. It maintains a constant water temperature by reducing the magnetron output power instead of switching it on and off, avoiding the impact on the power grid caused by frequent switching of the microwave heating component 2. This eliminates temperature fluctuations caused by the water temperature repeatedly crossing around 80℃ under on / off control, allowing the metal wall to continuously transfer heat to the hydraulic tank at a constant temperature difference, resulting in an approximately linear rise in oil temperature T1 without step-like fluctuations.

[0053] In some embodiments, the first preset temperature is 15°C, the second preset temperature is 50°C, and the third preset temperature is 80°C.

[0054] Specifically, the first preset temperature of 15℃ precisely corresponds to the minimum allowable oil temperature for starting the hydraulic oil pump of the coal mill. When the oil temperature is below this temperature, the hydraulic oil becomes viscous, causing the pump to fail to start. The second preset temperature of 50℃ corresponds to the upper limit of the normal operating temperature range of the hydraulic oil. When the oil temperature reaches this value, the viscosity of the hydraulic oil fully meets the power transmission requirements for the lifting and loading of the grinding rollers. This serves as the criterion for terminating heating, avoiding overheating and wasting energy.

[0055] The third preset temperature of 80℃ is the target temperature control for deionized water in the jacket cavity 3. This temperature is much lower than the boiling point of water at normal pressure (100℃) to retain a safety margin, and much higher than the 15℃ start-up threshold to form a temperature difference of at least 65℃ between the two sides of the wall, which is sufficient to drive heat from the water medium through the metal wall to the low-temperature hydraulic oil efficiently. The greater the temperature difference, the faster the heat transfer rate. The selection of 80℃ achieves the best balance between the safety of the water medium and the heating speed.

[0056] After the oil temperature starts below 15℃, the water temperature first rises to 80℃ and remains constant. Then, the oil temperature gradually rises from below 15℃ under continuous heating from a constant 80℃ heat source. Heating continues uninterrupted when the oil temperature crosses 15℃, continuing until it reaches 50℃ before stopping, ensuring that the heat source is not removed prematurely during the entire temperature rise process. The 30℃ difference between the constant 80℃ water temperature and the 50℃ stopping oil temperature provides a margin that allows the control system to maintain the water temperature at 80℃ until the oil temperature reaches 50℃ before triggering a stop, ensuring that the heating window is always driven by the maximum permissible heat source temperature. The temperature difference between the 80℃ constant water temperature and the 50℃ stopping oil temperature also ensures that there is still a 30℃ positive temperature difference between the two sides of the metal wall at the moment the oil temperature reaches the stopping threshold. The heat flow direction on the wall is always unidirectional, from water to oil. After heating stops, residual heat from the water can continue to transfer a small amount of heat to the oil side for a short time, preventing the oil temperature from exceeding 50℃ excessively due to continued rise from residual heat after stopping.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0061] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A microwave water jacket intelligent rapid heating device for a hydraulic oil station of a coal mill in a thermal power plant, characterized in that, include: A hydraulic oil tank body is used to contain hydraulic oil. A jacketed cavity is fitted on the outer wall of the hydraulic oil tank body. The jacketed cavity has a metal wall surface facing the hydraulic oil tank body. The jacketed cavity is filled with a heat exchange medium. A microwave heating assembly is arranged on the jacket cavity to microwave heat the heat exchange medium in the jacket cavity, and the heat is indirectly conducted to the hydraulic oil tank body through the metal wall. A temperature detection component, comprising an oil temperature sensor and a water temperature sensor, wherein the oil temperature sensor is used to monitor the oil temperature inside the hydraulic oil tank body, and the water temperature sensor is used to monitor the temperature inside the jacket cavity; and the control unit is signal-connected to the oil temperature sensor and the water temperature sensor. The control unit is electrically connected to the microwave heating component. The control unit controls the start / stop and output power of the microwave heating component based on the input oil temperature signal and water temperature signal.

2. The intelligent rapid heating device for microwave water jacket of hydraulic oil station in coal mill of thermal power plant according to claim 1, characterized in that, It also includes a circulation mechanism, which comprises a circulating water pump and inlet / outlet pipes. The inlet / outlet pipes are respectively connected to the inlet and outlet of the circulating water pump to form a circulation loop. The circulation loop is connected to the jacket cavity, and the circulating water pump is electrically connected to the control unit. The circulating water pump is used to provide circulation power.

3. The intelligent rapid heating device for microwave water jacket of hydraulic oil station in coal mill of thermal power plant according to claim 1, characterized in that, It also includes a central water storage and heat storage tank, which is connected in parallel with multiple independent jacketed cavities through pipelines to form a heat exchange network.

4. The intelligent rapid heating device for microwave water jacket of hydraulic oil station in coal mill of thermal power plant according to claim 1, characterized in that, A flow guiding structure is provided inside the jacket cavity to guide the water flow inside the jacket cavity along a preset path.

5. The intelligent rapid heating device for microwave water jacket of hydraulic oil station of coal mill in thermal power plant according to claim 1, characterized in that, The microwave heating assembly includes a magnetron and a waveguide connected to the magnetron. The waveguide emits microwaves oriented toward the jacket cavity and is electrically connected to the control unit.

6. The intelligent rapid heating device for microwave water jacket of hydraulic oil station in coal mill of thermal power plant according to claim 5, characterized in that, The magnetron has a transmission frequency of 2450MHz.

7. The intelligent rapid heating device for microwave water jacket of hydraulic oil station of coal mill in thermal power plant according to claim 1, characterized in that, The jacket cavity is provided with a water inlet, a sewage outlet, and a sealing element, the sealing element being used to seal the water inlet and the sewage outlet.

8. The intelligent rapid heating device for microwave water jacket of hydraulic oil station of coal mill in thermal power plant according to claim 1, characterized in that, The heat exchange medium filled in the jacket cavity is deionized water.

9. The intelligent rapid heating device for microwave water jacket of hydraulic oil station of coal mill in thermal power plant according to claim 1, characterized in that, The control unit controls the microwave heating component based on the oil temperature T1 monitored by the oil temperature sensor. When T1 is less than the first preset temperature, the microwave heating component is activated. When T1 is less than the second preset temperature, the microwave heating assembly is stopped. The control unit controls the output power of the microwave heating component based on the water temperature T2 monitored by the water temperature sensor. When T2 reaches the third preset temperature, the control unit adjusts the output power of the microwave heating component to maintain the water temperature at the third preset temperature.

10. The intelligent rapid heating device for microwave water jacket of hydraulic oil station of coal mill in thermal power plant according to claim 1, characterized in that, The first preset temperature is 15℃, the second preset temperature is 50℃, and the third preset temperature is 80℃.

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