960 results about "Bypass valve" patented technology

The invention relates to the technical field of fault diagnosis of industrial cooling equipment, and discloses a fault diagnosis early warning method and system for double bypass valves of an industrial cooler. According to the method, a state feature vector is constructed by obtaining real-time operation parameters, dynamic time sequence analysis is carried out on the state feature vector to calculate a sliding entropy value and a Lyapunov index, state evolution trend features are determined, a fault feature index is calculated in combination with the valve opening degree and a control signal deviation value, and an early warning threshold value is determined based on historical data distribution variance. And when the index exceeds a threshold value, determining a fault type and outputting early warning information. The potential fault of the bypass valve can be predicted in advance, the false alarm rate is reduced, and the diagnosis precision is improved.

The invention relates to a paraffin type thermostat. The paraffin type thermostat comprises a main valve 1, a cover and seal gasket assembly 2, an upper support 3, a rubber pipe 4, a valve seat 5, a vent hole 6, a lower support 7, paraffin 8, an inductor 9, a bypass valve 10, a central rod 11 and a spring 12. The upper support, the lower support and the valve seat of the thermostat are riveted into a whole. The upper end of the central rod is fixed to the center of the upper support. The lower portion of the central rod is inserted into a central hole of the rubber pipe. The lower end of the central rod is conical. A cavity between the rubber pipe and a shell of the inductor contains the paraffin. The upper portion and the lower portion of the shell of the inductor are provided with the main valve and the bypass valve which are in linkage. The vent hole is formed in the main valve. The paraffin type thermostat is high in heat conductivity and guarantees that an engine cannot be excessively cold.

Embodiments of the invention provide a high density liquid cooling system including a rack, primary loop piping including a primary inlet, a primary outlet, a primary loop filter, and a primary bypass valve, and secondary loop piping including a secondary inlet, a secondary outlet, a first pump, a first filter downstream of the first pump, and a secondary bypass valve. The system includes a heat exchanger having a first side and a second side. When the primary bypass valve is open, at least a portion of the fluid in the primary loop piping flows through the primary inlet and the primary outlet without traversing the heat exchanger, and when the secondary bypass valve is open, at least a portion of the fluid in the secondary loop piping flows through the secondary inlet and the secondary outlet without traversing the heat exchanger.

The utility model belongs to the technical field of water heaters, and particularly discloses a gas water heater which comprises a water inlet pipe, a heat exchanger and a water outlet pipe which are sequentially communicated in the water flow direction, and further comprises a water mixing tank and a bypass pipe, the water mixing tank is arranged on the water outlet pipe, and a water inlet, a bypass water inlet and a water outlet are formed in the water mixing tank. The water inlet is used for being communicated with the water outlet end of the heat exchanger, the water outlet is communicated with the water using end through the water outlet pipe, the two ends of the bypass pipe are communicated with the bypass water inlet and the water inlet pipe respectively, a bypass valve used for adjusting the water flow is arranged on the bypass pipe, and the vertical distance H1 between the bypass water inlet and the water inlet is larger than the vertical distance H2 between the bypass water inlet and the water outlet. According to the gas water heater disclosed by the utility model, on the basis of solving the problem of water stop temperature rise during secondary starting, the outlet water temperature in the water stop temperature drop stage can be improved, and the structure of the water mixing tank is simplified while the water stop temperature drop is effectively improved.

The invention relates to the technical field of heat pump control, and discloses a defrosting method and device of a heat pump system and the heat pump system.The defrosting method comprises the steps that the temperature and humidity of gaps of a fin type heat exchanger are monitored in real time; and when the temperature is lower than or equal to the threshold value of the dynamic dew point temperature plus the safety margin and the humidity is higher than or equal to the threshold value, it is judged that the frosting prevention condition is met, the gap temperature is increased by adjusting the refrigerant bypass valve, the gap humidity is reduced by adjusting the airflow adjusting valve, and therefore frosting is actively prevented. And if the frost layer appears, short-time refrigeration interruption or low-power heating is started for defrosting according to the thickness of the frost layer or a pressure difference signal. And the formed ice layer is forcibly removed by switching the flow direction of the refrigerant and heating. By means of three-level linkage control, accurate defrosting in the whole process from prevention to removal is achieved, energy waste is effectively avoided, the defrosting efficiency and operation stability of the system are improved, and the user experience is improved.

The invention discloses a cooperative control method based on an air compressor and a bypass valve in a fuel cell load reduction process, and relates to the field of surge prevention of a fuel cell system, and the cooperative control method comprises the following steps: obtaining the air flow at an inlet of the air compressor, the rotating speed of the air compressor and the excess oxygen ratio; calculating the surge flow lower limit of the corresponding compressor based on the rotating speed of the air compressor; when the air flow of the inlet of the air compressor is lower than the multiple of the lower surge limit of the compressor, the bypass valve opening value a is increased to the initial bypass valve opening value to obtain an anti-surge opening value, and the rotating speed of the air compressor is synchronously increased to the first rotating speed; when the air flow at the inlet of the air compressor is higher than the surging lower limit of the compressor and the oxygen excess ratio is greater than or equal to the minimum peroxide ratio; the fuel cell stack inlet cathode pressure is obtained, and the bypass valve opening degree is controlled through PI based on the fuel cell stack inlet cathode pressure and the anti-surge opening degree value. According to the invention, combined anti-surge and anti-hypoxia control based on the air compressor and the bypass valve can be realized in the load reduction process of the fuel cell system.

The invention discloses a double-machine regenerative steam-electricity double-drive small turbine thermodynamic system and a control method, belongs to the technical field of power generation, and aims to solve the problem that steam extraction parameter reduction and system power balance maintenance cannot be both considered in the prior art. According to the system, the MCT is adopted to extract exhaust steam of the ultrahigh-pressure cylinder to drive the water feeding pump and the variable-frequency generator, and meanwhile, a low-superheat-degree steam source is provided for the multi-stage heater. When P is greater than Pmax, executing at least one of the following control strategies: (a) adjusting the opening degree of a steam inlet valve of the MCT; (b) the opening degree of an MCT steam exhaust valve is adjusted; (c) adjusting the opening degree of a heater bypass valve; the steam exhaust pressure of the MCT is kept stable through three-way closed-loop control, and safe and efficient operation is achieved by combining power compensation of the variable-frequency generator.

The demister cleaning device comprises a first-effect evaporation module, a second-effect evaporation module, a third-effect evaporation module and a feeding pipe, the first-effect evaporation module, the second-effect evaporation module and the third-effect evaporation module are sequentially connected through the feeding pipe, and a third-effect demister in the third-effect evaporation module is connected to a condenser and a centrifugal water vapor compressor through a three-way pipe. The centrifugal water vapor compressor is connected into a first-effect heater in the first-effect evaporation module through a pipeline; a bypass valve is connected to the pipeline between the condenser and the first-effect heater and connected with the centrifugal water vapor compressor in parallel. A top inlet of the triple-effect demister is connected with a high-pressure water inlet pipe. Secondary steam generated by triple effect is recycled instead of directly entering the condenser to be condensed, the recycled secondary steam enters the centrifugal steam compressor to pressurize the triple effect secondary steam, and the triple effect secondary steam is supplied to the first-effect heater to be used for heating materials to replace original live steam, so that the purposes of saving energy and reducing consumption are achieved.

A filter unit includes a body portion that receives a water filter. An engaging portion is coupled to the body portion. A bypass actuator rotates relative to the engaging portion to rotationally and axially operate a bypass valve of a fluid manifold. The bypass actuator drives axial engagement of the engaging portion with a valve assembly of the fluid manifold. The bypass actuator extends through the body portion and the engaging portion.

The invention provides a liquid cooling system cooling capacity distribution unit control method, device and unit and a liquid cooling system. The method comprises the steps that current hydraulic parameters of cooling liquid in a secondary side liquid supply and return pipeline are obtained; if the current hydraulic parameter is smaller than a preset hydraulic threshold value and the absolute difference value between the current hydraulic parameter and the preset hydraulic threshold value is larger than a first preset difference value, the frequency of a circulating pump and / or the opening degree of a bypass valve are / is adjusted according to the current hydraulic parameter and the preset hydraulic threshold value so as to increase the flow of cooling liquid in a secondary side liquid supply and return pipeline; and if the current hydraulic parameter is larger than a preset hydraulic threshold value and the absolute difference value is larger than a first preset difference value, the frequency of a circulating pump and / or the opening degree of a bypass valve are / is adjusted according to the current hydraulic parameter and the preset hydraulic threshold value so as to reduce the flow of the cooling liquid in the secondary side liquid supply and return pipeline. Heat dissipation control can be carried out timely and accurately, the heat dissipation performance of the liquid cooling system is improved, the heat dissipation requirement of the server is met, and normal operation of the server is guaranteed.

The invention belongs to the technical field of water source heat pump units, and particularly relates to a self-checking method of a vortex type water source heat pump unit, which comprises the following steps: 1, controlling a bypass valve to open according to a set period and driving a sampling pump through a controller in a detection part on the water source heat pump unit, and introducing a water source sample into a sampling tank in the detection part from a main pipeline, and the controller is electrically connected with a built-in control module of the detection component through an RS485 bus so as to transmit instructions. According to the self-checking method of the vortex type water source heat pump unit, by arranging the self-checking method of the vortex type water source heat pump unit, water quality self-checking can be conducted on the water source heat pump unit automatically and regularly, the water quality is detected through a pH sensor, a turbidimeter, a conductivity meter and a metal ion detector, the weight is dynamically adjusted through water sources, a segmented normalization algorithm is adopted, and the self-checking accuracy of the vortex type water source heat pump unit is improved. And the misjudgment problem of adapting to all water sources according to a fixed standard is avoided.

Embodiments of the present application provide a turbocharger control method, device, equipment and readable storage medium. The method comprises: obtaining a running condition corresponding to a vehicle; determining a surge line corresponding to a turbocharger, the surge line being used to represent airflow oscillation phenomenon of gas along the axial direction of the compressor; in the case that the running condition and the surge line meet a preset relationship, adjusting a first opening angle of a waste gate valve, or adjusting a second opening angle of a vehicle power pedal. The purpose of making the running condition of the vehicle away from the surge line is achieved, and then the turbocharger is in a normal working state, avoiding the turbocharger emitting high-frequency Hiss noise to bring negative driving experience to the driver.

The invention provides a valve device. The valve device comprises a main valve component, a bypass valve component and a communicating pipe. When the medium pressure difference of the inflow runner part and the outflow runner part of the main valve part reaches the preset value, the first valve port part of the bypass valve part can be opened for pressure relief, the bypass valve part and the main valve part are integrated, and the problem that the pressure relief function is lost due to reverse installation of the bypass valve part does not exist. The bypass valve component is provided with the pressure gauge connector part, the bypass valve component has a bypass function and a cut-off function, a channel between the pressure gauge connector part and the main valve component can be cut off, and the safety problem when the pressure gauge is connected is solved.

The invention relates to a novel double-temperature water path air conditioning system and a control method thereof. A main loop of a cold water (heat pump) unit in the system comprises a compressor, a four-way reversing valve, a first / second / third heat exchanger, a first throttling / second throttling element and a gas-liquid separator, and a bypass branch (with a bypass valve) is additionally arranged; and two independent secondary refrigerant loops are arranged to be connected with the indoor environment in a heat exchange manner. Cold generated by evaporation heat absorption of a refrigerant and heat generated by condensation heat release are synchronously utilized and conveyed into a room through a secondary refrigerant, and the flow of the secondary refrigerant at the tail end is adjusted, so that the heat-humidity ratio in the air treatment process is adjusted, and decoupling treatment and dynamic matching of a single unit to heat and humidity loads are achieved. And under the high-humidity load working condition, one path of secondary refrigerant utilizes cold energy to cool and dehumidify indoor air, and the other path of secondary refrigerant utilizes supercooling heat and / or condensation heat to carry out reheating temperature control on the air. Under the working condition of high sensible heat load, the two paths of secondary refrigerants cooperate for refrigerating / heating, and the unified output capacity meets the peak load requirement.

The invention provides a hydraulic cooler double-bypass-valve pressure self-adaptive adjusting method and system, and relates to the technical field of hydraulic systems.The method comprises the steps that a fluctuation trend characteristic value is calculated by reading pressure data, characteristic matching is carried out to generate an adjusting instruction, temperature and flow data are collected in real time in a monitoring period, and oil viscosity and Reynolds number are calculated; and when a flow state transition control mode is entered, calculating an optimal flow velocity based on a pressure gradient, converting the optimal flow velocity into a double-bypass valve target opening degree combination, and establishing a mapping relation between an opening degree value and a pressure response by utilizing a steady-state working condition database. Accurate pressure control of the hydraulic system is achieved, and the stability of the system is improved.

The invention discloses a heat energy power generation system based on efficient Rankine cycle and a control method. An outlet of a working medium pump included in the heat energy power generation system is connected with a heat regenerator cold side inlet through a heat regenerator cold side bypass valve. The heat regenerator cold side bypass valve is connected with a working medium inlet of the cooling liquid heat exchanger; a working medium outlet of the cooling liquid heat exchanger is respectively connected with inlets of the turbine bypass valve and the turbine inlet valve; an outlet of the turbine inlet valve is connected with a working medium inlet of the turbine power generation all-in-one machine; a working medium outlet of the turbine power generation all-in-one machine is connected with a hot side inlet of the heat regenerator through a turbine outlet valve; a hot side outlet of the heat regenerator is connected with a working medium inlet of the condenser; a condenser working medium outlet is connected with a liquid storage tank inlet; the liquid storage tank is connected with the working medium pump; the outlet of the cooling channel is connected with the working medium inlet of the condenser; and the outlet of the cooling channel is connected with the working medium inlet of the turbine power generation all-in-one machine. The low-boiling-point organic working medium is adopted to absorb cooling liquid heat of external devices (such as brake pads), and consumption reduction and efficiency improvement are achieved.

The application discloses a carbon dioxide refrigeration heat pump system and a composite control method of the carbon dioxide refrigeration heat pump system. The carbon dioxide refrigeration heat pump system comprises a first compressor, a second compressor, a third compressor, a water cooler, a first regenerator, a first throttling valve, a flash tank, a second throttling valve, an evaporator, a liquid storage barrel, a flash bypass valve and a second regenerator which are connected and matched with each other. The carbon dioxide refrigeration heat pump system and the composite control method have the advantages that the design is scientific, the working condition of the carbon dioxide refrigeration heat pump system can be accurately controlled, the control precision is improved, the working condition energy efficiency is obviously improved, the operation efficiency of the working condition is ensured, and the application has great practical significance. The composite control method of the carbon dioxide refrigeration heat pump system specially designed by the application is a dimension reduction decoupling control method for coping with the operation of a complex system with variable working conditions.

To inhibit temperature rise of a hydraulic fluid effectively to prevent seizure of a hydraulic pump.SOLUTION: A hydraulic device 4 includes: a hydraulic cylinder 10; and a hydraulic pressure supply / discharge device 5 which expands or contracts the hydraulic cylinder 10. The hydraulic pressure supply / discharge device has: a bypass oil passage B which is branched from a first oil passage 41 extending from the discharge side of a hydraulic pump 15 to a spool of a switching valve 16 and disposed so that its downstream end returns a hydraulic fluid to an oil tank 17; a bypass valve 19 which may open or close the bypass oil passage; and linkage means which links the spool and the bypass valve to each other. At least a part of the bypass oil passage B is formed in a bypass pipe 18 provided outside of casings 24, 31. The linkage means links the spool and the bypass valve to each other so that the hydraulic fluid discharged from the hydraulic pump flows through the bypass pipe when a switching position of the spool is in a neutral position and the hydraulic fluid discharged from the hydraulic pump does not flow through the bypass pipe when the switching position of the spool is in a lifted position.SELECTED DRAWING: Figure 5

A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. A bypass valve (BPV) includes a BPV inlet in fluid communication with the outlet line, and a BPV outlet in fluid communication with a bypass line that feeds into the inlet line upstream of the VDP. A minimum pressure shutoff valve (MPSOV) is connected in fluid communication with the outlet line, configured to block flow through the outlet line for shutoff. The MPSOV is connected in fluid communication with the BPV for triggering recirculation through the BPV.

A fuel filtering system comprising a fuel filter having an input, an output and a washing path. The fuel filter may be cylindrical in shape. The system further comprising a bypass valve having an input from the washing path, and a drain, wherein when the cylindrical fuel filter has a pressure drop from the input to the output, the bypass valve opens to permit cleaning of the filter by allowing fuel to flow from the washing path to the drain. The bypass valve comprises a spool, a valve seat and a spring that has a spring rate (Sk). The output is may be provide through an input to the bypass valve, behind the spool.

The invention discloses a multifunctional spray-seeding device for mining area slope vegetation recovery. The multifunctional spray-seeding device comprises a spray-seeding main loop assembly, a circulating degassing steady-state assembly and a pulse diagnosis and active damping control assembly. The spray-seeding main loop assembly is used for continuously conveying spray-seeding slurry to the spray head from the mixing end and forming controlled spraying; the circulating degassing steady-state assembly is used for establishing reflux circulation before spraying and during spraying interval and realizing gas stripping and slurry steady-state maintenance; the pulse diagnosis and active damping control assembly is used for carrying out pulse response examination on the loop state before spraying is started and providing adjustable damping and switching curve control in the spraying starting process. According to the device, a closed loop mechanism of a controllable micro-pulse bypass valve and near-far end double-pressure response examination is introduced into a spray-seeding main loop; and the compressibility and the equivalent friction resistance of the air bag are recognized, a soft start switching curve and an active damping strategy are generated in a self-adaptive mode, and stable starting and continuous and uniform spraying of the multi-highest-point long pipeline under frequent stopping and starting are achieved.

The invention discloses a control method and system for a comprehensive energy supply system of a double-source heat pump building, and relates to the technical field of heating, ventilation and air conditioning, and the control method comprises the following steps: collecting conductivity data, extracting a characteristic frequency component of the conductivity data, and judging the state of a phase change material through the characteristic frequency component; an adjusting instruction of the double-source heat pump is triggered according to the state of the phase change material, and a double-source heat pump energy supply mode is output; evaporation reference values are matched for different dual-source heat pump energy supply modes, the frequency of a compressor is adjusted according to the reference deviation, and a variable frequency driving signal is generated; dynamically adjusting compressor frequency and electronic expansion valve opening according to the variable frequency driving signal, monitoring inlet and outlet pressure difference of an evaporator after adjustment, and judging whether bypass valve shunting is carried out or not; a heat recovery channel is activated in bypass valve shunting, and energy recovery and energy supply regulation and control are completed. Through cooperation of conductivity characteristic frequency analysis and dynamic activation of the heat recovery channel, accurate judgment of the state of the phase change material and closed-loop regulation and control of energy flow are achieved.

The invention discloses an engine oil filter with a spiral spoiler. The engine oil filter comprises a bottom shell, an outer cover is fixedly connected to the bottom shell, a liquid inlet and a liquid outlet are formed in the bottom shell, a check valve is arranged on the liquid inlet, a connecting cylinder is fixedly connected into the liquid outlet, a filter element structure is fixedly connected to the connecting cylinder, and a bypass valve is arranged on the filter element structure; the flow guide assembly comprises a first spiral spoiler, the first spiral spoiler is located between the filter element structure and the outer cover, the first spiral spoiler is rotationally connected to the annular base, the bypass valve is fixedly connected with the annular base through a connecting mechanism, a supporting mechanism is fixedly connected into the outer cover, and a stop mechanism is arranged between the supporting mechanism and the annular base. Impurities of engine oil can be prevented from being gathered at a certain position, the use of a filtering part is more balanced, the durability of the device is improved, meanwhile, oil liquid can flow along the spoiler during operation, and large particles generate centrifugal force, so that the oil liquid is thrown to the wall surface and flows to the bottom along the spoiler, and the blockage degree of the filter element is reduced.

This invention provides a bypass valve and a water heater incorporating the same, belonging to the field of water heater technology. The bypass valve includes a valve body with an inlet channel, an outlet channel, a first channel, a second channel, and a connecting channel. It also includes a first valve core assembly, a second valve core, a driving component, and a first reset component. The first valve core assembly is configured to be movable to a predetermined position. The driving component drives the first valve core assembly to rotate around the axis of the first channel. The second valve core includes a mating portion and a blocking portion. The mating portion is located within the first channel, and the blocking portion is located within the second channel. When the first valve core assembly moves to the predetermined position, it drives the mating portion to rotate, causing the blocking portion to rotate from the first position to the second position, thus reducing the opening of the second channel. The first reset component drives the blocking portion to rotate from the second position to the first position, thus increasing the opening of the second channel. By changing the opening of the second channel, the bypass flow rate is adjusted.

This utility model relates to the field of drilling technology for soil or rock layers, specifically to a one-way bypass valve for a screw drill and the screw drill itself. The drill includes a one-way bypass valve for unidirectional drilling fluid flow. The one-way bypass valve includes a valve body with a valve sleeve inside its inner bore. A one-way valve is located at the outlet end of the valve sleeve. The one-way valve includes a one-way valve seat with a support plate at the end furthest from the valve sleeve. The support plate has a drain hole for drilling fluid passage. A compression spring is also provided on the support plate, and a valve block is located at the other end of the spring. The one-way valve seat has a shoulder near the valve sleeve to stop the valve block. The spring force causes the valve block to abut or disengage from the shoulder, thus closing or opening the one-way valve seat. The compression spring in this utility model is positioned below the valve block, preventing the valve block and spring from being washed away by the drilling fluid with significant impact force, thereby improving the reliability of the entire device.

This application provides an integrated oil-cooled structure, an electric drive system, and a vehicle. The system includes an oil cooler with an internal bypass oil passage, and an oil inlet and outlet connected to the bypass oil passage. A bypass valve includes a valve core assembly and a connector. At least a portion of the valve core assembly is located within the bypass oil passage. One end of the connector is connected to the valve core assembly, and the other end abuts against the bypass oil passage. The valve core assembly is located on the bypass oil passage near the oil inlet. When the amount of oil entering the bypass oil passage through the inlet does not exceed a preset value, the bypass oil passage is in a conducting state. When the amount of oil exceeds the preset value, the valve core assembly moves to switch the bypass oil passage to a closed state. This integrated design minimizes the overall structure and reduces the number of oil passages and interface seals.

The invention discloses a full-dynamic-pressure turbine type low-temperature refrigerating device and method. The device comprises a two-stage centrifugal compressor, a heat exchanger, a low-temperature turbine expander, a gas storage tank, a filter, a valve, a water cooling machine and a cold using device. Closed circulation is adopted in the device, and the whole device is integrated into a skid-mounted device to output cooling capacity outwards. The device adopts a full-dynamic-pressure turbine type structure and is supported by a gas bearing; the low-temperature turbine expander and the low-temperature heat exchanger are in a heat insulation environment; the low-temperature turbo expander adopts pressurization braking or fan braking; a three-stage integrated heat exchanger or a separated heat exchanger is adopted for skid-mounting; the skid-mounted system comprises a charging mode and a non-charging mode. The whole device runs without oil, and is clean and environment-friendly; the integration level of the system is greatly improved through the three-stage integrated heat exchanger and the skid-mounted structure; different braking modes are set, so that the applicability of the device is improved; the refrigerating temperature and the refrigerating capacity can be accurately controlled through the full-pressurization mode, the partial-pressurization mode and the bypass valve.

The invention relates to a filter system (100) for filtering fluids, in particular a liquid filter system, comprising a filter head (112) and a replaceable filter element (10) that is functionally integrated into the filter housing part (114). The filter head (112) includes a bypass valve (30) that controls a bypass fluid flow (142) between a fluid inlet (102) and a fluid outlet (104) in a bypass mode. The bypass valve (30) comprises a valve assembly (32) with at least one bolt (40) arranged on a seat (118) of the filter head (112), a piston (50) with a central bore (52) for slidably engaging along the bolt (40), and a spring element (60) arranged at a first end (62) on the piston (50) and at a second end (64) on the bolt (40). The invention further relates to a filter head (112).

The invention belongs to the field of chemical engineering, and particularly relates to an HPCO methanation treatment system and a system isolation operation technology, the HPCO methanation treatment system comprises a raw material supply unit, a first methanation reaction unit, a second methanation reaction unit, a heat recovery unit and a load isolation unit; according to the invention, the load isolation unit is matched with the first methanation reaction unit and the second methanation reaction unit, the second methanation reaction unit is isolated from the system when being overhauled, and the raw material supply unit, the first methanation reaction unit and the heat recovery unit in the system still continue to work at the moment, so that the overall shutdown of the HPCO methanation treatment system is avoided; in an isolated operation process based on the system, heat of a reaction product of the first methanation reaction unit is effectively exchanged by regulating and controlling the second inlet regulating valve, the first bypass valve, the second bypass valve and the sixth control valve, and the problem that heat is unbalanced during independent operation of the first methanation reaction unit is effectively solved.

A cooling system for an aircraft fuel cell system includes a coolant pump to circulate coolant through the cooling system and a radiator to reject heat to ambient air. A cooler zone is provided downstream of the radiator, comprising a plurality of parallel cooling branches. A warmer zone is provided downstream of the cooler zone, the warmer zone including a fuel cell stack. A bypass valve is arranged to provide coolant to the warmer zone from upstream of the radiator. A restrictor may be arranged to provide coolant to the warmer zone from downstream of the radiator.