Dual-channel drainage and pressure-equalizing air supply type heat pump waste heat recovery system and industrial drum clothes dryer

Abstract

The present application relates to heat pump waste heat recovery and industrial drying equipment technical field, especially in kind of double -way drainage pressure -equalizing air supply formula heat pump waste heat recovery system and industrial drum clothes dryer, including first condenser, second condenser and steam supplement heat exchanger's air flow channel along heating air duct series connection, first condenser is located upstream, and one of the latter two is located downstream and constitutes the last stage heating component.Two drainage fans will be the air discharged by the last stage heating component respectively introduced into two diversion branch, after the output of the flow equalization.The controller adjusts two drainage fans according to the dry air mass flow of two branches, so that the branch flow keeps balance and the total flow reaches the target value.The clothes dryer adopts the above system, so that the fresh air is heated in stages and then enters the drum, and the waste heat of the wet hot exhaust air is recovered by two-stage evaporator.The present application can improve the uniformity and stability of high-temperature air supply, reduce the risk of local overheating and air backflow.

Description

Technical Field

[0001] This invention relates to the technical field of heat pump waste heat recovery and industrial drying equipment, and particularly to a dual-path flow equal pressure air supply heat pump waste heat recovery system and an industrial drum dryer. Background Technology

[0002] Existing industrial drum dryers can recover waste heat from the humid air discharged from the drum. The heat pump system absorbs heat from the humid exhaust air through an evaporator and heats the incoming fresh air through a condenser; when the heat provided by the heat pump is insufficient for high-temperature drying, a steam supplementary heat exchanger can be used. However, existing technologies still have the following shortcomings:

[0003] (1) The high-temperature air discharged from the final stage condenser usually needs to go through a long air supply path and turn to enter the drum. The existing air duct is insufficient in terms of air diffusion, convergence and turning, which easily generates large pressure drop, local eddies and uneven lateral air volume.

[0004] (2) In wide-range condensers or multi-fan air supply structures, airflow imbalances can easily occur between different air outlet areas and air supply branches. Even if the airflow of different air supply branches is made basically equal by adjusting the fans, the uneven distribution of refrigerant inside the condenser may still result in inconsistent outlet air temperature and heat exchange power between different air outlet areas. Existing equipment usually uses the total air supply volume or the airflow of each air supply branch as the control basis, making it difficult to coordinate and adjust the airflow and refrigerant heat distribution simultaneously.

[0005] (3) When the air supply flow is unbalanced, if the compressor and steam heat exchanger continue to increase the air temperature, it is easy to cause local overheating on the air outlet side of the condenser or the air supply duct. The linkage protection between air supply control and heating control is still imperfect.

[0006] (4) When high-temperature air enters the drum from a local location, the air volume at the near end of the drum is large and the air volume at the far end is small, which affects the uniformity of heating of clothes and drying efficiency.

[0007] (5) When some of the air supply fans fail, air backflow may occur in the air supply branch, and the residual heat in the condenser, steam heat exchanger and air supply duct cannot be discharged in time, posing a risk of local heat accumulation.

[0008] Therefore, it is necessary to further improve the high-temperature air supply path, branch flow balance, heating linkage control, drum air distribution, and fault exhaust structure of the heat pump waste heat recovery system. Summary of the Invention

[0009] To address at least one of the technical problems in the prior art, the present invention aims to provide a dual-flow, pressure-equalizing, air-supplying heat pump waste heat recovery system.

[0010] To address at least one of the technical problems in the prior art, the present invention aims to provide an industrial drum dryer.

[0011] The first objective of this invention is achieved as follows:

[0012] A dual-path pressure-equalizing air-supplying heat pump waste heat recovery system includes a casing, a first heat pump system, a second heat pump system, a steam heat exchanger, and an exhaust fan. The first heat pump system includes a first compressor, a first condenser, a first throttling device, and a first evaporator connected sequentially in a first refrigerant circulation loop via refrigerant piping. The second heat pump system includes a second compressor, a second condenser, a second throttling device, and a second evaporator connected sequentially in a second refrigerant circulation loop via refrigerant piping. The casing is provided with a fresh air inlet, a hot air outlet, a humid air inlet, and an exhaust vent. A heating duct is formed between the fresh air inlet and the hot air outlet, and a heating duct is formed between the humid air inlet and the exhaust vent. A waste heat recovery duct is formed; along the airflow direction within the waste heat recovery duct, the second evaporator, the first evaporator, and the exhaust fan are sequentially arranged; when the first heat pump system and the second heat pump system operate simultaneously, the evaporation saturation temperature and condensation saturation temperature of the second heat pump system are respectively higher than those of the first heat pump system; the steam supplementary heat exchanger has mutually isolated steam flow channels and air flow channels for heat exchange, and the steam flow channel is provided with a steam inlet for communication with an external steam source; the air inlet side of the first condenser is connected to the fresh air inlet; the airflow of the first condenser, the second condenser, and the steam supplementary heat exchanger... The airflow paths within the heating duct are connected in series, with the first condenser located upstream of the airflow paths of the second condenser and the steam heat exchanger. The second condenser and the steam heat exchanger located downstream along the airflow path constitute the final heating stage. The dual-path induced flow equalization airflow heat pump waste heat recovery system further includes a guiding duct, a first induced flow fan, and a second induced flow fan. The guiding duct includes a first guiding inlet, a second guiding inlet, a first guiding branch connected to the first guiding inlet, a second guiding branch connected to the second guiding inlet, a convergence and equalization section connected to the first guiding branch and the second guiding branch respectively, and a section connected to... The air supply section is connected to the confluence and equalization section; the first guide inlet and the second guide inlet are both located at the top of the casing and downstream of the final stage heating component along the airflow direction; the first induced flow fan and the second induced flow fan are respectively disposed between the final stage heating component and the corresponding guide inlet, the air inlet of each induced flow fan is disposed facing the air outlet of the final stage heating component, and the air outlet of each induced flow fan is respectively connected to the corresponding guide inlet to form two parallel induced flow paths entering the induced flow duct from the air outlet of the final stage heating component; the air supply section extends from the confluence and equalization section to the front of the casing, and the outlet of the air supply section constitutes the hot air outlet.

[0013] By connecting the air channels of the first condenser, the second condenser, and the steam supplementary heat exchanger in series, and allowing the second condenser to be arranged in different sequences with the air channels, the appropriate staged heating path can be selected according to the heat pump heating capacity, external steam conditions, and target supply air temperature. At the same time, the high-temperature air discharged from the final stage heating component is introduced into two parallel ducting paths by the first and second ducting fans, and then merged and transported to the hot air outlet at the front of the casing through the ducting air. This helps to solve the problems of poor high-temperature air delivery, excessive air volume concentration, and local heat accumulation when the heating component and the drum air inlet are far apart, and improves the continuity and stability of high-temperature air delivery.

[0014] The primary objective of this invention can also be achieved using the following technical measures:

[0015] Furthermore, the airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component; the air outlet side of the second condenser is divided into a first air outlet area and a second air outlet area along the width direction of the second condenser, with the first and second induced draft fans spaced apart along the width direction of the second condenser and corresponding to the first and second air outlet areas respectively; the air outlet side of the second condenser is provided with a first and a second induced draft hood respectively covering the first and second air outlet areas, with both the first and second induced draft hoods having an inlet facing the second condenser and a constricted air outlet facing the corresponding induced draft fan, and the flow cross-sectional area gradually decreasing from the inlet to the constricted air outlet; the inlet of the first induced draft fan is sealed and connected to the constricted air outlet of the first induced draft hood, and the inlet of the second induced draft fan is sealed and connected to the constricted air outlet of the second induced draft hood.

[0016] By dividing the air outlet side of the second condenser into a first air outlet area and a second air outlet area, and using the first and second collectors to collect the air from the corresponding air outlet areas respectively, the mutual interference of air in the width direction of the second condenser can be reduced. The flow cross-sectional area of ​​the collector gradually decreases from the collection port to the narrow air outlet end, and is sealed and connected with the corresponding induced draft fan, which is conducive to smoothly collecting the air from a larger area to the air inlet of the induced draft fan, reducing air leakage and local short circuits, and improving the air collection capacity and heat exchange uniformity of each air outlet area of ​​the second condenser.

[0017] Furthermore, the housing has a longitudinal intermediate surface extending along its front-rear direction. The first and second flow guide branches are located on both sides of the longitudinal intermediate surface and extend from the rear to the front of the housing. The flow cross-sectional areas of the first and second flow guide branches gradually increase along the airflow direction. The effective flow cross-sectional area of ​​the converging and equalizing section at the junction with the first and second flow guide branches is not less than the sum of the effective flow cross-sectional areas of the first and second flow guide branches at their corresponding junctions. The converging and equalizing section is provided with a converging guide member located between the first and second flow guide branches. The converging guide member has two arc-shaped flow guide surfaces facing the first and second flow guide branches respectively. The two arc-shaped flow guide surfaces are smoothly connected to the inner walls of the corresponding flow guide branches. The converging guide member gradually narrows from its upstream end to its downstream end so that the two streams of air converge into the air supply section in the same direction.

[0018] By gradually increasing the flow cross-sectional area of ​​the first and second guide branches along the airflow direction, the air velocity within the branches can be reduced and the dynamic pressure before the air converges can be decreased. The effective flow cross-sectional area of ​​the confluence and equalization section is not less than the sum of the corresponding cross-sectional areas of the two guide branches, which can prevent sudden contraction at the air convergence point. At the same time, the gradually narrowing confluence guide uses two arc-shaped guide surfaces to guide the two air streams to smoothly change direction and merge into the air supply section, thereby reducing the eddies and pressure loss generated by the direct collision of the two air streams and improving the stability of the confluence process.

[0019] Furthermore, the air supply section includes a curved air supply section for changing the airflow direction. The curved air supply section is provided with multiple spaced arc-shaped deflector vanes. The tangent direction of the upstream end of each arc-shaped deflector vane is consistent with the airflow direction in the converging and equalizing section, and the tangent direction of the downstream end of each arc-shaped deflector vane is consistent with the air outlet direction of the hot air outlet, so as to stratify and deflect the air after it has been converged in the converging and equalizing section and deliver it to the hot air outlet.

[0020] By installing multiple arc-shaped deflector vanes within the curved air supply section, and aligning the upstream and downstream ends of these vanes with the corresponding airflow directions, the converging air can be divided into multiple layers and its flow direction gradually changed. This reduces airflow separation, impact on the duct wall, and the formation of local vortices within the curved air supply section, thereby lowering local resistance at the deflection point and improving the stability of airflow direction and volume distribution at the hot air outlet.

[0021] Furthermore, the flow equalization section is provided with a flow equalization plate spanning the flow equalization section on the downstream side of the flow guide member, and the flow equalization plate is provided with a plurality of ventilation holes; the flow equalization plate includes a windward area opposite to the air outlet direction of the first flow guide branch and the second flow guide branch respectively, and a compensation area located outside each windward area, wherein the porosity of the windward area is less than the porosity of the compensation area.

[0022] By setting up flow equalization plates with different porosity regions within the confluence and equalization section, and ensuring that the windward region facing the air outlet direction of the two guide branches has a smaller porosity, a greater resistance can be applied to the high-speed air rushing towards the flow equalization plate. The compensation region located outside the windward region has a larger porosity, which can improve the air passage capacity of the surrounding low-flow area, thereby redistributing the air within the cross-section of the confluence and equalization section, reducing the local wind speed difference, and improving the airflow uniformity at the inlet of the air supply section.

[0023] Furthermore, the first and second diversion branches are respectively equipped with a first branch main air mass flow rate detector and a second branch main air mass flow rate detector. The first and second diversion fans are both variable frequency fans with independently adjustable speeds. The dual-path diversion equalizing air supply heat pump waste heat recovery system also includes a controller. The first branch main air mass flow rate detector, the second branch main air mass flow rate detector, the first diversion fan, and the second diversion fan are electrically connected to the controller. The controller independently adjusts the operating frequency of the first and second diversion fans according to the detection results of the first and second branch main air mass flow rate detectors to change the speed of the first and second diversion fans, so that the difference in dry air mass flow rate between the first and second diversion branches is within a preset branch flow rate balance range, and the sum of the dry air mass flow rates of the two diversion branches reaches a preset total dry air mass flow rate.

[0024] By detecting the dry air mass flow rate in the first and second guide branches respectively, and independently adjusting the speed of the first and second guide fans by the controller, closed-loop regulation can be performed according to the actual air supply status of the two guide branches. This keeps the flow rate difference between the two guide branches within a preset range and ensures that the sum of their flow rates reaches the preset total dry air mass flow rate. This improves the problem that it is difficult to detect the flow imbalance of the branches in time when controlling only the total air supply volume, and enhances the stability of the air outlet of the final stage heating component and the subsequent air supply.

[0025] Furthermore, the airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component; the heating airflow duct is equipped with a first temperature sensor, a second temperature sensor, and a third temperature sensor to detect the air temperature at the outlet of the first condenser, the air temperature at the outlet of the airflow channel, and the air temperature at the outlet of the second condenser, respectively; the steam inlet is equipped with a steam regulating valve, and both the first compressor and the second compressor are variable frequency compressors with adjustable operating frequencies; the first temperature sensor, the second temperature sensor, the third temperature sensor, the steam regulating valve, the first compressor, and the second compressor are all electrically connected to the controller; in high-temperature drying mode, the controller adjusts the operating frequency of the first compressor and the opening / closing of the steam regulating valve according to the detection results of the first temperature sensor, the second temperature sensor, and the third temperature sensor, respectively. The controller adjusts the operating frequency of the first and second induced draft fans to ensure that the air temperature at the outlet of the airflow channel is higher than that at the outlet of the first condenser, and the air temperature at the outlet of the second condenser is higher than that at the outlet of the airflow channel. When the difference in dry air mass flow rate between the two induced draft fans exceeds the preset branch flow rate balance range, the controller prioritizes adjusting the operating frequency of the first and second induced draft fans to change their speed. Before the difference in dry air mass flow rate between the two induced draft fans returns to the preset branch flow rate balance range, the controller restricts the steam regulating valve from increasing its opening and restricts the second compressor from increasing its operating frequency. When the sum of the dry air mass flow rates of the two induced draft fans is lower than the preset safe dry air mass flow rate, the controller closes the steam regulating valve and controls the first and second compressors to reduce their operating frequencies or stop operating.

[0026] By separately detecting the outlet air temperatures of the first condenser, the steam heat exchanger, and the second condenser, and correspondingly adjusting the first compressor, the steam regulating valve, and the second compressor, the air temperature can be gradually increased in a predetermined sequence to stabilize the supply air temperature required for high-temperature drying. When the flow rates of the two guide branches are unbalanced, the controller prioritizes adjusting the induced draft fan and temporarily limits the opening of the steam regulating valve and the operating frequency of the second compressor from continuing to increase. When the total dry air mass flow rate is lower than the safe value, the controller promptly stops or reduces the heat input, thereby avoiding local overheating caused by continued heating when the air supply is insufficient or uneven, and improving the safety of system operation.

[0027] Furthermore, the airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component; the air outlet side of the second condenser is divided into a first air outlet area and a second air outlet area along the width direction of the second condenser, with the first and second induced draft fans corresponding to the first and second air outlet areas respectively; the first and second induced draft branches are respectively equipped with a first branch main air mass flow rate detector and a second branch main air mass flow rate detector, and both the first and second induced draft fans are variable frequency fans whose speed can be independently adjusted; the dual-path induced draft equalizing air supply heat pump waste The heat recovery system also includes a controller, and the second compressor is a variable frequency compressor with adjustable operating frequency; the second condenser includes a refrigerant inlet manifold, a refrigerant outlet manifold, and a first condensing branch and a second condensing branch connected in parallel between the refrigerant inlet manifold and the refrigerant outlet manifold, the first condensing branch and the second condensing branch being respectively arranged corresponding to the first air outlet area and the second air outlet area; the inlet side of the first condensing branch and the second condensing branch are respectively provided with a first refrigerant flow regulating valve and a second refrigerant flow regulating valve, and the downstream side of the first air outlet area and the second air outlet area are respectively provided with a first zone air outlet temperature detection element and a second condensing branch. The second zone outlet air temperature detection device; the first branch dry air mass flow rate detection device, the second branch dry air mass flow rate detection device, the first induced draft fan, the second induced draft fan, the first refrigerant flow regulating valve, the second refrigerant flow regulating valve, the first zone outlet air temperature detection device, the second zone outlet air temperature detection device, and the second compressor are respectively electrically connected to the controller; the controller first adjusts the first induced draft fan and the second induced draft fan according to the detection results of the first branch dry air mass flow rate detection device and the second branch dry air mass flow rate detection device, so that the difference in dry air mass flow rate between the two induced draft branches is within the preset branch flow rate. Within the equilibrium range; after the difference in dry air mass flow rate is within the preset branch flow equilibrium range and remains stable for a preset time, when the difference in air temperature detected by the first zone outlet air temperature detector and the second zone outlet air temperature detector exceeds the preset zone temperature difference range, the controller increases the opening of the refrigerant flow regulating valve corresponding to the outlet air area with lower outlet air temperature and decreases the opening of the refrigerant flow regulating valve corresponding to the outlet air area with higher outlet air temperature, so that the sum of the openings of the first refrigerant flow regulating valve and the second refrigerant flow regulating valve remains within the preset total opening range until the air temperature difference between the two outlet air areas returns to the preset zone temperature difference range;When the air temperature in both air outlet zones is simultaneously higher or lower than the preset target air outlet temperature of the second condenser, the controller maintains the opening ratio between the first refrigerant flow regulating valve and the second refrigerant flow regulating valve unchanged, and adjusts the operating frequency of the second compressor.

[0028] By separately detecting the dry air mass flow rate of the two guide branches and independently adjusting the first and second induced draft fans, the heat exchange difference caused by uneven air flow between the two outlet areas can be eliminated first. After the air flow rate reaches equilibrium and stabilizes, the first and second refrigerant flow regulating valves are adjusted in reverse according to the temperature difference between the two outlet areas, and the sum of the openings of the two valves is kept within the preset total opening range. This can correct the refrigerant distribution between the two condensing branches while suppressing large fluctuations in the total refrigerant flow rate. When the temperature of the two outlet areas is simultaneously too high or too low, the overall outlet temperature of the second condenser can be regulated by maintaining the opening ratio of the two valves and adjusting the operating frequency of the second compressor. Thus, it is possible to distinguish and sequentially handle air flow imbalance, refrigerant distribution imbalance, and overall temperature deviation, reduce the temperature difference and heat exchange power difference between the two outlet areas, avoid the problem that adjusting only the induced draft fans is insufficient to eliminate the zone temperature difference, improve the uniformity and stability of the second condenser outlet air and subsequent air supply, and reduce the risk of local overheating.

[0029] The second objective of this invention is achieved as follows:

[0030] An industrial drum dryer includes a casing, a drum, a drum drive unit, a first heat pump system, a second heat pump system, a steam heat exchanger, an exhaust fan, and a lint filter. The drum is rotatably mounted inside the casing. The drum drive unit is connected to the drum for driving the drum to rotate. The casing has a fresh air inlet and an exhaust outlet, and a clothes loading / unloading opening corresponding to the drum. The drum has an air inlet side and an air outlet side, with the air inlet side located near the clothes loading / unloading opening. The first heat pump system includes a first compressor, a first condenser, a first throttling device, and a first evaporator, which are sequentially connected in a first refrigerant circulation loop via refrigerant piping. The second heat pump system includes a second compressor, a second condenser, a second throttling device, and a second evaporator, which are sequentially connected in a second refrigerant circulation loop via refrigerant pipelines. The steam heat exchanger has mutually isolated steam and air channels for heat exchange, and the steam channel has a steam inlet for communication with an external steam source. When the first and second heat pump systems operate simultaneously, the evaporation saturation temperature and condensation saturation temperature of the second heat pump system are higher than those of the first heat pump system, respectively. The first condenser, the steam heat exchanger, and the second condenser are all located on the top of the casing and extend along the... The casing is arranged sequentially from front to back. The industrial drum dryer also includes a guide air duct, a first guide fan, and a second guide fan. The guide air duct includes a first guide inlet and a second guide inlet located at the top of the casing and behind the second condenser, a first guide branch connected to the first guide inlet, a second guide branch connected to the second guide inlet, a convergence and equalization section connected to the two guide branches respectively, and an air supply section extending from the convergence and equalization section to the front of the casing. The outlet of the air supply section is connected to the air inlet side of the drum. The first guide fan and the second guide fan are respectively disposed between the second condenser and the corresponding guide inlet. In this configuration, the air inlets of each of the aforementioned induced draft fans are all positioned facing the air outlet side of the second condenser, and the air outlets of each of the aforementioned induced draft fans are respectively connected to the corresponding guide inlets to form two parallel induced draft paths from the air outlet side of the second condenser into the guide air duct; a through-type air passage is formed inside the casing, and along the air flow direction within the through-type air passage, the fresh air inlet, the first condenser, the air flow duct, the second condenser, the two parallel induced draft paths, the guide air duct, the air inlet side of the drum, the air outlet side of the drum, the lint filter, the second evaporator, the first evaporator, the exhaust fan, and the exhaust outlet are sequentially connected.

[0031] By creating a continuous air passage within the industrial drum dryer, outside air is sequentially heated by the first condenser, the steam reheat heat exchanger, and the second condenser. It is then transported to the air inlet side of the drum via two parallel flow paths and a guide duct. The hot, humid air discharged from the drum passes through a lint filter and then flows sequentially through the second and first evaporators. This allows for seamless integration of air heating, clothes drying, and exhaust waste heat recovery processes. The second and first evaporators recover waste heat at higher and lower temperatures, respectively, which improves the utilization rate of exhaust waste heat and reduces external heat consumption during the high-temperature drying process.

[0032] The second objective of this invention can also be achieved by the following technical measures:

[0033] Furthermore, the air inlet side of the roller is provided with an air distribution cavity, which at least partially surrounds the outer periphery of the clothing loading and unloading opening. The outlet of the air supply section is connected to the air distribution cavity. The air distribution cavity is provided with a plurality of air outlets facing the inner cavity of the roller along its extension direction. The air distribution cavity is divided into a plurality of equal-length sections along its extension direction. Along the direction away from the outlet of the air supply section, the total flow area of ​​the air outlets in each of the equal-length sections gradually increases. Each air outlet is provided with an air inlet guide plate, which makes the air entering the inner cavity of the roller have a velocity component along the axial direction of the roller and a velocity component along the circumferential direction of the roller.

[0034] By setting an air distribution cavity that at least partially surrounds the clothes loading and unloading opening on the air inlet side of the drum, and making the equal-length section far from the air supply section outlet have a large total air distribution area, the pressure loss caused by the air flowing along the air distribution cavity can be compensated, and the problem of large air volume near the air supply section outlet and insufficient air volume at the far end can be improved. The air inlet guide vane makes the air entering the drum have both axial and circumferential velocity components, which can promote the high-temperature air to advance along the drum axis and diffuse along the drum circumferentially, thereby improving the air inlet uniformity, clothes heating uniformity and drying efficiency.

[0035] Furthermore, check valves are respectively provided between the air outlet of the first induced draft fan and the first guide inlet, and between the air outlet of the second induced draft fan and the second guide inlet, to allow air to flow only towards the guide duct; the steam inlet is provided with a steam regulating valve, and the industrial drum dryer also includes a controller; both the first compressor and the second compressor are variable frequency compressors with adjustable operating frequencies; the first induced draft fan is provided with a first fan operating status detection device, and the second induced draft fan is provided with a second fan operating status detection device; the first guide branch and the second guide branch are respectively provided with a first branch main air mass flow detection device and a second branch main air mass flow detection device; the first fan operating status detection device, the second fan operating status... The detection device, the first branch dry air mass flow rate detection device, the second branch dry air mass flow rate detection device, the first induced draft fan, the second induced draft fan, the steam regulating valve, the first compressor, the second compressor, and the exhaust fan are all electrically connected to the controller. When the first fan operation status detection device or the second fan operation status detection device detects that the corresponding induced draft fan has malfunctioned, or when the dry air mass flow rate of any induced draft branch is lower than the preset minimum dry air mass flow rate of the branch for a preset time, the controller closes the steam regulating valve, controls the first compressor and the second compressor to reduce their operating frequency or stop operating, and allows the induced draft fan and the exhaust fan, which are in normal operating condition, to continue operating for a preset heat dissipation time.

[0036] By installing backflow preventers between each induced draft fan and its corresponding inlet, air can be prevented from flowing back through the faulty branch when one of the induced draft fans stops. At the same time, by detecting the operating status of the induced draft fans and the dry air mass flow rate of the corresponding guide branch, induced draft fan malfunctions or abnormal branch flow can be identified in a timely manner. The controller can then close the steam regulating valve, reduce or stop the compressor operation, allowing the normally operating induced draft fans and exhaust fans to continue to discharge the waste heat in the equipment. This reduces air backflow and local heat accumulation in fault conditions, improving the operational reliability and safety of the equipment.

[0037] The beneficial effects of this invention are as follows:

[0038] In this invention, the first heat pump system and the second heat pump system can respectively recover waste heat at different temperature levels in the humid exhaust air, and perform multi-stage heating of the fresh air through the air flow channels of the first condenser, the second condenser and the steam supplementary heat exchanger; the second condenser and the air flow channels can be arranged in different sequences according to the heating capacity of the heat pump, the external steam conditions and the target supply air temperature, so as to improve the utilization rate of exhaust waste heat and reduce steam consumption and external energy consumption while meeting the high-temperature drying requirements.

[0039] In this invention, high-temperature air from different air outlet areas of the second condenser is collected by a shroud, and the air is guided by two induced draft fans, two guide branches, a convergence and pressure equalization section, a convergence guide component, a flow equalization plate, and an arc-shaped deflector. This reduces air collision, local eddies, and pressure loss during the air supply process, and improves the airflow uniformity at the air outlet of the second condenser and the hot air outlet.

[0040] In this invention, by separately detecting the dry air mass flow rate of the two guide branches and the air temperature after each stage of heating, and by coordinating and controlling the two guide fans, two compressors and steam regulating valves, the air supply temperature can be adjusted while maintaining the balance between the total air supply volume and the branch flow rate. In case of insufficient air supply, branch imbalance or fan failure, the heat input can be restricted or stopped in time and the residual heat can be discharged, thereby reducing the risk of local overheating and air backflow.

[0041] In this invention, by setting an air distribution cavity, an air outlet with progressively increasing flow area, and an air inlet guide plate on the air inlet side of the drum, the pressure loss along the flow path in the air distribution cavity can be compensated, allowing high-temperature air to enter the drum more evenly and form an airflow with axial and circumferential velocity components, thereby improving the problem of uneven heating of clothes and improving drying efficiency and drying quality. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention.

[0043] Figure 2 This is another schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention.

[0044] Figure 3 This is a cross-sectional view of the industrial drum dryer in Embodiment 1 of the present invention.

[0045] Figure 4 This is a schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention (door open).

[0046] Figure 5 This is a schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention (with part of the machine casing hidden).

[0047] Figure 6 This is a schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention (partially disassembled).

[0048] Figure 7 This is another schematic diagram of the industrial drum dryer in Embodiment 1 of the present invention (partially disassembled).

[0049] Figure 8 This is a schematic diagram of the airflow in the through-type air passage in Embodiment 1 of the present invention.

[0050] Figure 9 This is a schematic diagram showing the connection relationship between the first heat pump system, the second heat pump system, and the steam supplementary heat exchanger in Embodiment 1 of the present invention.

[0051] Figure 10 This is a schematic diagram of the dual-path parallel flow diversion structure on the air outlet side of the second condenser in Embodiment 1 of the present invention.

[0052] Figure 11 This is a schematic diagram of the overall structure of the first diversion branch, the second diversion branch, the confluence and equalization section, the flow equalization plate, and the air supply section in Embodiment 1 of the present invention.

[0053] Figure 12 This is a front view of the flow equalization plate in Embodiment 1 of the present invention.

[0054] Figure 13 This is a schematic diagram of the electrical connection relationship between the controller, the detection device, and the controlled component in Embodiment 1 of the present invention.

[0055] Figure 14 This is a schematic diagram of the airflow in the through-type air passage in Embodiment 2 of the present invention.

[0056] Figure 8 , Figure 10 , Figure 11 and Figure 14 Solid arrows indicate the direction of airflow; Figure 9 The thick solid arrows located outside the heat exchanger indicate the direction of air flow, the thin solid arrows in the refrigerant lines indicate the direction of refrigerant flow, and the dashed arrows indicate the direction of steam and condensate flow. Figure 12 The dashed box in the image represents the boundary between the two windward areas; Figure 13 The arrows in the diagram indicate the direction of transmission of the detection or control signal. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0058] Example 1

[0059] In this embodiment, the side of the housing 10 with the clothing loading and unloading opening 74 is taken as the front part of the housing 10, the side opposite to the front part is taken as the rear part of the housing 10, and the horizontal direction perpendicular to the front and rear direction of the housing 10 is taken as the width direction of the housing 10; the longitudinal middle surface of the housing 10 is a vertical plane that extends along the front and rear direction of the housing 10 and passes through the middle of the width direction of the housing 10.

[0060] like Figures 1 to 13As shown, this embodiment 1 provides an industrial drum dryer. The industrial drum dryer includes a casing 10, a first heat pump system, a second heat pump system, a steam replenishment heat exchanger 40, an exhaust fan 50, a controller 60, a drum 70, a drum drive device 71, a lint filter 72, a condensate discharge device 73, a guide air duct 80, a first induced draft fan 90, and a second induced draft fan 91. The casing 10, the first heat pump system, the second heat pump system, the steam replenishment heat exchanger 40, the exhaust fan 50, the controller 60, the guide air duct 80, the first induced draft fan 90, and the second induced draft fan 91 together constitute a dual-path induced draft equalization air supply type heat pump waste heat recovery system.

[0061] The housing 10 is provided with a fresh air inlet 11, a hot air outlet 12, a humid air inlet 13, and an exhaust outlet 14. A heating air duct is formed between the fresh air inlet 11 and the hot air outlet 12, and a waste heat recovery air duct is formed between the humid air inlet 13 and the exhaust outlet 14. A roller 70 is rotatably mounted inside the housing 10, and a roller drive device 71 is driven by the roller 70 to drive the roller 70 to rotate. The roller 70 has an air inlet side 701 and an air outlet side 702. The air inlet side 701 is located near the clothing loading / unloading opening 74. The housing 10 is also provided with a door 75 for opening or closing the clothing loading / unloading opening 74. The hot air outlet 12 is connected to the air inlet side 701 of the roller 70, and the air outlet side 702 of the roller 70 is connected to the waste heat recovery air duct via a lint filter 72 and the humid air inlet 13.

[0062] The first heat pump system includes a first compressor 21, a first condenser 22, a first electronic expansion valve 23 (serving as a first throttling device), and a first evaporator 24. The discharge port of the first compressor 21, the first condenser 22, the first electronic expansion valve 23, the first evaporator 24, and the suction port of the first compressor 21 are sequentially connected through a first refrigerant pipeline 27 to form a first refrigerant circulation loop. A first suction temperature detector 25 and a first suction pressure detector 26 are provided at the suction port of the first compressor 21. The first electronic expansion valve 23, the first suction temperature detector 25, and the first suction pressure detector 26 are electrically connected to the controller 60. In this embodiment, the first refrigerant circulation loop is charged with R134a, and the first compressor 21 is a variable frequency compressor; all refrigerant pressures below are absolute pressures. Under rated operating conditions, the evaporation saturation temperature of the first heat pump system is 35°C, corresponding to an evaporation pressure of approximately 0.887 MPa, the condensation saturation temperature is 48°C, corresponding to a condensation pressure of approximately 1.253 MPa, and the suction superheat of the first compressor 21 is controlled between 5K and 8K.

[0063] The second heat pump system includes a second compressor 31, a second condenser 32, a second electronic expansion valve 33 (serving as a second throttling device), and a second evaporator 34. The discharge port of the second compressor 31, the second condenser 32, the second electronic expansion valve 33, the second evaporator 34, and the suction port of the second compressor 31 are sequentially connected through a second refrigerant pipeline 37 to form a second refrigerant circulation loop. A second suction temperature detector 35 and a second suction pressure detector 36 are provided at the suction port of the second compressor 31. The second electronic expansion valve 33, the second suction temperature detector 35, and the second suction pressure detector 36 are electrically connected to the controller 60. In this embodiment, the second refrigerant circulation loop is charged with R1233zd(E), and the second compressor 31 is a variable frequency compressor. The second compressor 31, the second electronic expansion valve 33, the second refrigerant pipeline 37, and their seals are all selected according to the compatibility of R1233zd(E) and the design temperature and design pressure of the second refrigerant circulation loop. The design temperature of the second condenser 32 is 180°C, and the design pressure is 4.0 MPa. The upper limit of the allowable discharge temperature of the second compressor 31 is 175°C. Under rated operating conditions, the evaporation saturation temperature of the second heat pump system is 50°C, corresponding to an evaporation pressure of approximately 0.293 MPa, and the condensation saturation temperature is 150°C, corresponding to a condensation pressure of approximately 2.736 MPa. The suction superheat of the second compressor 31 is controlled between 8K and 12K. Therefore, the evaporation saturation temperature and condensation saturation temperature of the second heat pump system are higher than those of the first heat pump system, respectively.

[0064] The steam supplementary heat exchanger 40 includes a steam distribution pipe 43, a condensate collection pipe 44, and multiple finned heat exchange tubes connected in parallel between the steam distribution pipe 43 and the condensate collection pipe 44. The internal space of each finned heat exchange tube collectively forms a steam flow channel 41, and the ventilation space between adjacent finned heat exchange tubes collectively forms an air flow channel 42. The steam flow channel 41 and the air flow channel 42 are isolated from each other and exchange heat through the finned heat exchange tubes. The air flow channel 42 has an air inlet 421 and an air outlet 422. The steam distribution pipe 43 is provided with a steam inlet 411 for communication with an external steam source, and the condensate collection pipe 44 is provided with a condensate outlet 412. The steam inlet 411 is provided with a steam regulating valve 48, and the condensate outlet 412 is connected to the condensate recovery pipe 493 via a steam trap 492. External steam is depressurized and enters the steam flow channel 41 at a gauge pressure of 0.30MPa to 0.40MPa. The steam releases heat and condenses in the finned heat exchange tube, and the condensate is discharged through the condensate outlet 412.

[0065] The first condenser 22, the steam supplementary heat exchanger 40, and the second condenser 32 are all located on the top of the casing 10 and arranged sequentially from the front to the rear of the casing 10 along the airflow direction within the heating duct. The air inlet side of the first condenser 22 is connected to the fresh air inlet 11, the air inlet end 421 of the airflow duct 42 is sealed and connected to the air outlet side of the first condenser 22, and the air outlet end 422 of the airflow duct 42 is sealed and connected to the air inlet side of the second condenser 32. In this embodiment, the second condenser 32 constitutes the final stage heating component. Air baffles are provided on the outer periphery of the first condenser 22, the steam supplementary heat exchanger 40, and the second condenser 32 to prevent air from bypassing the corresponding heat exchangers.

[0066] The outlet side of the second condenser 32 is divided into a first outlet region 321 and a second outlet region 322 along the width direction of the second condenser 32, and the widths of the first outlet region 321 and the second outlet region 322 are equal. The outlet side of the second condenser 32 is provided with a first collector shroud 92 and a second collector shroud 93 respectively covering the first outlet region 321 and the second outlet region 322. Both the first collector shroud 92 and the second collector shroud 93 have a collection port facing the second condenser 32 and a constricted outlet end facing the corresponding induced draft fan. The flow cross-sectional area of ​​each collector shroud from the collection port to the constricted outlet end is 0.18m². 2 Continuously decreased to 0.075m 2 The periphery of both the first and second air collection hoods 92 and 93 is sealed to the frame of the second condenser 32 by high-temperature resistant sealing strips, so that the air discharged from the first air outlet area 321 and the second air outlet area 322 enters the corresponding air collection hoods respectively.

[0067] The first induced draft fan 90 and the second induced draft fan 91 are spaced apart along the width direction of the second condenser 32 and are respectively positioned between the second condenser 32 and their corresponding guide inlets. The air inlets of both induced draft fans face the air outlet side of the second condenser 32. The air inlet of the first induced draft fan 90 is sealed and connected to the constricted air outlet end of the first collector shroud 92, and the air inlet of the second induced draft fan 91 is sealed and connected to the constricted air outlet end of the second collector shroud 93. Both the first induced draft fan 90 and the second induced draft fan 91 are high-temperature resistant variable frequency centrifugal fans whose operating frequency can be independently adjusted within the range of 20Hz to 60Hz. The axial distance between their air inlets and the air outlet side of the second condenser 32 is 80mm.

[0068] The guiding air duct 80 includes a first guiding inlet 81, a second guiding inlet 82, a first guiding branch 83, a second guiding branch 84, a convergence and equalization section 85, and an air supply section 86. Both the first guiding inlet 81 and the second guiding inlet 82 are located at the top of the casing 10 and behind the second condenser 32. The outlet of the first guiding fan 90 is sealed to the first guiding inlet 81 via a first check valve 94, and the outlet of the second guiding fan 91 is sealed to the second guiding inlet 82 via a second check valve 95. Both the first check valve 94 and the second check valve 95 allow air to flow only towards the guiding air duct 80, preventing air discharged from the other guiding fan from flowing in the opposite direction through the path of the stopped fan when either guiding fan stops. Thus, two parallel guiding paths are formed between the outlet side of the second condenser 32 and the guiding air duct 80.

[0069] The first guide branch 83 is connected to the first guide inlet 81, and the second guide branch 84 is connected to the second guide inlet 82. The first guide branch 83 and the second guide branch 84 are located on either side of the longitudinal mid-plane of the housing 10, extending from the rear to the front of the housing 10. The inlet cross-sectional area of ​​both guide branches is 0.075 m². 2 The outlet flow cross-sectional area is 0.110m². 2 The cross-sectional area of ​​each guide branch increases continuously along the airflow direction to reduce the airflow velocity and convert some of the dynamic pressure into static pressure. The length of the first guide branch 83 and the second guide branch 84 is 1.60m, and their inner wall corners are transitioned by arcs with a radius of not less than 150mm.

[0070] The confluence and equalization section 85 is connected to the outlets of the first guide branch 83 and the second guide branch 84, respectively. In this embodiment, the effective flow cross-sectional area refers to the net flow cross-sectional area of ​​the duct perpendicular to the average airflow direction at its location, minus the area occupied by the confluence guide 87, the equalization plate 88, and other internal components. The effective flow cross-sectional area of ​​the confluence and equalization section 85 at its connection with the two guide branches is 0.230 m². 2 It is greater than the sum of the effective flow cross-sectional areas of the two diversion branches at their corresponding junctions, which is 0.220m². 2 This avoids a significant pressure drop caused by the sudden contraction of the flow channel when the two air streams merge.

[0071] The converging and equalizing section 85 is equipped with a converging guide 87 located between the first guide branch 83 and the second guide branch 84. The converging guide 87 extends 420mm along the airflow direction, with a width of 150mm at its upstream end and 20mm at its downstream end, and continuously narrows from the upstream end to the downstream end. The converging guide 87 has a first arc-shaped guide surface 871 and a second arc-shaped guide surface 872 facing the first guide branch 83 and the second guide branch 84, respectively. The first arc-shaped guide surface 871 is smoothly connected to the inner wall of the first guide branch 83, and the second arc-shaped guide surface 872 is smoothly connected to the inner wall of the second guide branch 84, so that the two air streams gradually change direction during the converging process and enter the air supply section 86 in the same direction.

[0072] The confluence and equalization section 85 has a flow equalization plate 88 spanning across it, located 180 mm downstream of the confluence guide member 87. The surface of the flow equalization plate 88 is perpendicular to the average airflow direction within the confluence and equalization section 85. The flow equalization plate 88 has multiple ventilation holes 881 and is divided into two windward areas 882, respectively opposite to the airflow directions of the first guide branch 83 and the second guide branch 84, and a compensation area 883 located outside the two windward areas 882. The porosity is the ratio of the total area of ​​all ventilation holes 881 in the corresponding area to the area of ​​the plate in that area; the porosity of both windward areas 882 is 30%, and the porosity of the compensation area 883 is 45%. The windward area 882 uses ventilation holes 881 with a diameter of 10 mm, and the compensation area 883 uses ventilation holes 881 with a diameter of 14 mm, which makes the high dynamic pressure air facing the two guide branches subject to greater resistance and allows the air near the edge of the confluence and equalization section 85 to have greater flow capacity.

[0073] The air supply section 86 connects to the downstream end of the converging and equalizing section 85 and extends further towards the front of the casing 10 from the converging and equalizing section 85. The front end of the air supply section 86 is provided with a curved air supply section 861 that directs the airflow direction to the inlet side 701 of the roller 70. The curved air supply section 861 contains four spaced-apart arc-shaped deflector vanes 862. The tangent direction of the upstream end of each arc-shaped deflector vane 862 is consistent with the airflow direction within the converging and equalizing section 85, and the tangent direction of the downstream end of each arc-shaped deflector vane 862 is consistent with the outlet direction of the hot air outlet 12. The four arc-shaped deflector vanes 862 and the inner wall of the curved air supply section 861 together define five layered deflection channels. The outlet of the air supply section 86 constitutes the hot air outlet 12. The outer wall of the air supply section 86 is provided with a 50mm thick high-temperature resistant insulation layer to reduce heat loss during the return of high-temperature air to the front of the casing 10.

[0074] The air inlet side 701 of the roller 70 is provided with an air distribution cavity 77. The air distribution cavity 77 is U-shaped, extending along the upper side and left and right sides of the clothing loading and unloading opening 74, and at least partially surrounds the outer periphery of the clothing loading and unloading opening 74; the hot air outlet 12 is sealed and connected to one end of the air distribution cavity 77. The air distribution cavity 77 is divided into four equal-length sections, each 300mm long, along its extension direction. Each equal-length section is provided with multiple air distribution ports facing the inner cavity of the roller 70. Along the direction away from the hot air outlet 12, the total flow area of ​​the air distribution ports in the four equal-length sections is 260cm². 2 300cm 2 340cm 2 and 380cm 2 This compensates for the pressure loss along the flow path within the air distribution chamber 77.

[0075] Each air inlet is equipped with an air inlet guide vane. The air inlet guide vane is inclined at 20° towards the air outlet side 702 of the drum 70 in the axial plane of the drum 70, and deflected at 15° along the set rotation direction of the drum 70 in the cross-section of the drum 70. This ensures that the air entering the inner cavity of the drum 70 through the air inlet has both a velocity component along the axial direction of the drum 70 and a velocity component along the circumference of the drum 70. As a result, the high-temperature air forms a composite airflow that propels axially and rotates circumferentially within the drum 70, making full contact with the constantly tumbling clothes.

[0076] Along the airflow direction within the waste heat recovery duct, the second evaporator 34, the first evaporator 24, and the exhaust fan 50 are sequentially arranged. A lint filter 72 is provided between the air outlet side 702 of the drum 70 and the second evaporator 34, and a condensate drain device 73 is provided below the first evaporator 24 and the second evaporator 34. Thus, a through-type air passage is formed within the casing 10. Along the airflow direction within the through-type air passage, the following are sequentially connected: fresh air inlet 11, first condenser 22, airflow channel 42, second condenser 32, first and second manifold hoods 92 and 93, two parallel flow paths formed by the first and second induced draft fans 90 and 91, guide duct 80, hot air outlet 12, air distribution chamber 77, air inlet side 701 of the drum 70, air outlet side 702 of the drum 70, lint filter 72, humid and hot air inlet 13, second evaporator 34, first evaporator 24, exhaust fan 50, and exhaust port 14.

[0077] The first branch flow path 83 is equipped with a first branch air mass flow rate detector 68, and the second branch flow path 84 is equipped with a second branch air mass flow rate detector 69. The first branch air mass flow rate detector 68 includes a first temperature-resistant differential pressure measuring component, a first temperature and humidity sensing element, and a first absolute pressure sensing element. The second branch air mass flow rate detector 69 includes a second temperature-resistant differential pressure measuring component, a second temperature and humidity sensing element, and a second absolute pressure sensing element. Each temperature and humidity sensing element and each absolute pressure sensing element are disposed within their respective branch flow paths.

[0078] Each branch air mass flow rate detector determines the density and moisture content of the humid air in the corresponding guide branch based on the air temperature and relative humidity detected by the corresponding temperature and humidity detection element and the absolute pressure detected by the corresponding absolute pressure detection element. It also determines the humid air volumetric flow rate based on the differential pressure measurement result of the corresponding temperature-resistant differential pressure measurement component, the calibrated flow coefficient, the effective flow area, and the density of the humid air. Each branch air mass flow rate detector determines the humid air mass flow rate based on the humid air volumetric flow rate and the density of the humid air, and converts the humid air mass flow rate into dry air mass flow rate based on the moisture content, and outputs the dry air mass flow rate in the first guide branch 83 and the second guide branch 84 respectively.

[0079] The first induced draft fan 90 is equipped with a first fan operation status detection device 96, and the second induced draft fan 91 is equipped with a second fan operation status detection device 97; both fan operation status detection devices include a speed feedback terminal and a current detection terminal, which are used to determine whether the corresponding induced draft fan is operating normally.

[0080] The heating air duct is equipped with a first temperature sensor 61, a second temperature sensor 62, and a third temperature sensor 63. The first temperature sensor 61 is located on the air outlet side of the first condenser 22, the second temperature sensor 62 is located on the air outlet end 422 of the air flow channel 42, and the third temperature sensor 63 is located on the air outlet side of the second condenser 32. The first temperature sensor 61, the second temperature sensor 62, the third temperature sensor 63, the first branch main air mass flow rate sensor 68, the second branch main air mass flow rate sensor 69, the first fan operating status sensor 96, the second fan operating status sensor 97, the first induced draft fan 90, the second induced draft fan 91, the first compressor 21, the first electronic expansion valve 23, the first suction temperature sensor 25, the first suction pressure sensor 26, the second compressor 31, the second electronic expansion valve 33, the second suction temperature sensor 35, the second suction pressure sensor 36, the steam regulating valve 48, the exhaust fan 50, and the drum drive device 71 are all electrically connected to the controller 60.

[0081] The controller 60 determines the suction superheat of the first compressor 21 based on the detection results of the first suction temperature detector 25 and the first suction pressure detector 26, as well as the relationship between the pressure and saturation temperature of R134a, and adjusts the opening of the first electronic expansion valve 23 to maintain the suction superheat of the first compressor 21 at 5K to 8K. The controller 60 determines the suction superheat of the second compressor 31 based on the detection results of the second suction temperature detector 35 and the second suction pressure detector 36, as well as the relationship between the pressure and saturation temperature of R1233zd(E), and adjusts the opening of the second electronic expansion valve 33 to maintain the suction superheat of the second compressor 31 at 8K to 12K.

[0082] In this embodiment, the preset total dry air mass flow rate is set to 1.00 kg / s, and the preset branch flow balance range is set such that the absolute value of the difference between the dry air mass flow rates of the first guide branch 83 and the second guide branch 84 is not greater than 0.05 kg / s. During normal operation, the controller 60 determines the sum of the dry air mass flow rates of the two guide branches and the difference between the dry air mass flow rates of the two guide branches based on the detection results of the first branch dry air mass flow rate detector 68 and the second branch dry air mass flow rate detector 69. When the sum of the dry air mass flow rates of the two guide branches is less than 1.00 kg / s, the controller 60 increases the operating frequency of the first induced draft fan 90 and the second induced draft fan 91 in the same direction; when the sum of the dry air mass flow rates of the two guide branches is greater than 1.00 kg / s, the controller 60 decreases the operating frequency of the first induced draft fan 90 and the second induced draft fan 91 in the same direction. When the absolute value of the difference in dry air mass flow rate between the two guide branches is greater than 0.05 kg / s, the controller 60 performs differential regulation on the first guide fan 90 and the second guide fan 91, increasing the operating frequency of the guide fan corresponding to the guide branch with the lower dry air mass flow rate and decreasing the operating frequency of the guide fan corresponding to the guide branch with the higher dry air mass flow rate. When the sum of the dry air mass flow rates of the two guide branches deviates from the preset total dry air mass flow rate, and the difference in dry air mass flow rates between the two guide branches exceeds the preset branch flow rate balance range, the controller 60 superimposes the same-direction regulation amount used to regulate the total dry air mass flow rate with the differential regulation amount used to regulate the difference in dry air mass flow rates between the two guide branches, forming the respective operating frequency regulation amounts for the first guide fan 90 and the second guide fan 91, until the difference in dry air mass flow rates returns to the preset branch flow rate balance range, and the sum of the dry air mass flow rates reaches the preset total dry air mass flow rate. At this point, the dry air mass flow rates of the two diversion branches stabilized at around 0.50 kg / s.

[0083] In the high-temperature drying mode, the target air temperatures corresponding to the first temperature sensor 61, the second temperature sensor 62, and the third temperature sensor 63 are set to 36℃, 95℃, and 138℃ respectively. The controller 60 adjusts the operating frequency of the first compressor 21 based on the detection result of the first temperature sensor 61, adjusts the opening of the steam regulating valve 48 based on the detection result of the second temperature sensor 62, and adjusts the operating frequency of the second compressor 31 based on the detection result of the third temperature sensor 63, so that the air temperature at the outlet 422 of the airflow channel 42 is higher than the air temperature at the outlet side of the first condenser 22, and the air temperature at the outlet side of the second condenser 32 is higher than the air temperature at the outlet 422 of the airflow channel 42.

[0084] When the absolute value of the difference in dry air mass flow rate between the two guide branches is greater than 0.05 kg / s, the controller 60 preferentially adjusts the operating frequency of the first guide fan 90 and the second guide fan 91 to restore the difference in dry air mass flow rate between the two guide branches to the aforementioned preset branch flow rate balance range. Before the difference in dry air mass flow rate is restored to the aforementioned preset branch flow rate balance range, the controller 60 restricts the steam regulating valve 48 from increasing its opening degree and restricts the second compressor 31 from increasing its operating frequency to avoid further increasing the air temperature and forming local high temperatures when the air outlet of the second condenser 32 is uneven.

[0085] In this embodiment, limiting the steam regulating valve 48 from increasing its opening includes setting the opening of the steam regulating valve 48 to an upper limit of the allowable opening when a branch flow imbalance occurs, ensuring that the subsequent opening of the steam regulating valve 48 does not exceed this upper limit, or prohibiting the controller 60 from outputting a control command to the steam regulating valve 48 to increase its opening before the difference in dry air mass flow rate returns to the aforementioned preset branch flow balance range. Limiting the second compressor 31 from increasing its operating frequency includes setting the operating frequency of the second compressor 31 to an upper limit of the allowable frequency when a branch flow imbalance occurs, ensuring that the subsequent operating frequency of the second compressor 31 does not exceed this upper limit, or prohibiting the controller 60 from outputting a control command to the second compressor 31 to increase its operating frequency before the difference in dry air mass flow rate returns to the aforementioned preset branch flow balance range. These limitations do not prevent the controller 60 from reducing the opening of the steam regulating valve 48 or lowering the operating frequency of the second compressor 31 according to temperature or safety control needs.

[0086] As an optional embodiment, when the second condenser 32 constitutes the final stage heating component, the second condenser 32 further includes a refrigerant inlet manifold, a refrigerant outlet manifold, and a first condensing branch and a second condensing branch connected in parallel between the refrigerant inlet manifold and the refrigerant outlet manifold. The first condensing branch and the second condensing branch are respectively arranged corresponding to the first air outlet area 321 and the second air outlet area 322 to transfer heat to the air flowing through the first air outlet area 321 and the second air outlet area 322. A first refrigerant flow regulating valve and a second refrigerant flow regulating valve are respectively arranged on the inlet side of the first condensing branch and the second condensing branch. The first zone air outlet temperature detection element is arranged inside the first manifold 92 and located between the first air outlet area 321 and the first induced draft fan 90, and the second zone air outlet temperature detection element is arranged inside the second manifold 93 and located between the second air outlet area 322 and the second induced draft fan 91. The first refrigerant flow regulating valve, the second refrigerant flow regulating valve, the first zone outlet air temperature detection element, the second zone outlet air temperature detection element, and the second compressor 31 are all electrically connected to the controller 60. The second compressor 31 is a variable frequency compressor with adjustable operating frequency.

[0087] During normal operation, the controller 60 first adjusts the speeds of the first induced draft fan 90 and the second induced draft fan 91 based on the detection results of the first branch main air mass flow rate detector 68 and the second branch main air mass flow rate detector 69, respectively, so that the absolute value of the difference in dry air mass flow rate between the two induced draft branches is not greater than 0.05 kg / s. After the difference in dry air mass flow rate remains within the above range and reaches a preset stabilization time, the controller 60 initiates zoned heat balance control. When the difference in air temperature detected by the first zone outlet air temperature detector and the second zone outlet air temperature detector exceeds the preset zoned temperature difference range, the controller 60 increases the opening of the refrigerant flow regulating valve corresponding to the outlet air area with lower outlet air temperature, while decreasing the opening of the refrigerant flow regulating valve corresponding to the outlet air area with higher outlet air temperature, and keeps the sum of the openings of the first refrigerant flow regulating valve and the second refrigerant flow regulating valve within the preset total opening range, until the air temperature difference between the first outlet air area 321 and the second outlet air area 322 returns to the preset zoned temperature difference range. When the air temperature in both air outlet areas is simultaneously higher than the preset target air outlet temperature of 138°C for the second condenser 32, the controller 60 maintains the opening ratio between the first refrigerant flow regulating valve and the second refrigerant flow regulating valve unchanged and reduces the operating frequency of the second compressor 31; when the air temperature in both air outlet areas is simultaneously lower than the preset target air outlet temperature of 138°C, the controller 60 maintains the opening ratio between the two refrigerant flow regulating valves unchanged without triggering safety limits and increases the operating frequency of the second compressor 31.

[0088] As a preferred parameter setting example, this embodiment sets the preset stabilization time to 10 seconds, the preset zone temperature difference range to a maximum absolute value of the difference between the air temperatures detected by the first zone outlet air temperature detector and the second zone outlet air temperature detector, and the preset total opening range to 95%–105%. The valve opening of the refrigerant flow regulating valve in this embodiment refers to the percentage determined based on the effective full stroke of the corresponding refrigerant flow regulating valve from the fully closed position to the fully open position, where the fully closed position corresponds to 0% and the fully open position corresponds to 100%. The total opening of the first and second refrigerant flow regulating valves is the arithmetic sum of the percentage openings of the two valves; therefore, the total opening is 0% when both valves are fully closed and 200% when both valves are fully open. When starting the zone heat balance control, the initial opening of both the first and second refrigerant flow regulating valves is set to 50%, at which point the total opening of the two valves is 100%.

[0089] When the absolute value of the difference in dry air mass flow rate between the two guide branches is no greater than 0.05 kg / s for 10 consecutive seconds, the controller 60 initiates zoned heat balance control. For example, when the opening degree of both the first and second refrigerant flow regulating valves is 50%, the air temperature detected by the first zone outlet air temperature sensor is 135℃, and the air temperature detected by the second zone outlet air temperature sensor is 139℃, the controller 60 increases the opening degree of the first refrigerant flow regulating valve from 50% to 52%, and decreases the opening degree of the second refrigerant flow regulating valve from 50% to 48%. After each adjustment, it is held for 5 seconds, and then the air temperature of the two outlet air zones is compared again; if the absolute value of the temperature difference is still greater than 2℃, the adjustment continues in the same direction by one step. During this adjustment process, it is preferable to keep the total opening degree of the two valves at 100%, and allow them to be within the preset total opening degree range of 95% to 105% under the influence of valve control resolution and action error, until the absolute value of the air temperature difference between the two outlet air zones is no greater than 2℃.

[0090] During the zoned heat balance control process, if the absolute value of the difference between the dry air mass flow rate detected by the first branch main air mass flow rate detector 68 and the second branch main air mass flow rate detector 69 is again greater than 0.05 kg / s, the controller 60 suspends the adjustment of the opening of the first refrigerant flow rate regulating valve and the second refrigerant flow rate regulating valve, and prioritizes restoring the air-side flow balance of the two guide branches through the first induced flow fan 90 and the second induced flow fan 91; after the difference in dry air mass flow rate returns to the above range and continues to reach a preset stable time, the zoned heat balance control is resumed. Thus, the first induced flow fan 90 and the second induced flow fan 91 are used to balance the air-side flow rate, the first refrigerant flow rate regulating valve and the second refrigerant flow rate regulating valve are used to correct the refrigerant-side heat distribution between the two air outlet areas, and the second compressor 31 is used to adjust the total heat input of the second condenser 32, thereby reducing the air outlet temperature difference and heat exchange power difference that still exist between the two air outlet areas when only the air flow rates of the two guide branches are equal.

[0091] In this embodiment, the preset safe dry air mass flow rate is set to 0.80 kg / s. When the sum of the dry air mass flow rates of the two guide branches is less than 0.80 kg / s, the controller 60 immediately closes the steam regulating valve 48 and controls the first compressor 21 and the second compressor 31 to reduce their operating frequency; when the sum of the dry air mass flow rates of the two guide branches remains less than 0.80 kg / s for 5 seconds, the controller 60 stops the first compressor 21 and the second compressor 31.

[0092] In this embodiment, the minimum dry air mass flow rate of the preset branch is set to 0.35 kg / s, the preset time is set to 3 seconds, and the preset heat dissipation time is set to 180 seconds. When the first fan operation status detection device 96 or the second fan operation status detection device 97 detects a malfunction in the corresponding induced draft fan, or when the dry air mass flow rate of any induced draft branch is lower than 0.35 kg / s for 3 seconds, the controller 60 closes the steam regulating valve 48, stops the first compressor 21 and the second compressor 31, and allows the induced draft fan and exhaust fan 50, which are in normal operating condition, to continue running for 180 seconds. The first check valve 94 or the second check valve 95 automatically closes after the corresponding induced draft fan stops, allowing the normally operating induced draft fan to continue dissipating the residual heat in the casing 10 and the induced draft duct 80.

[0093] When starting the high-temperature drying mode, the controller 60 first starts the exhaust fan 50, the first induced draft fan 90, and the second induced draft fan 91, and makes the two induced draft fans operate at an initial operating frequency of 30Hz. When the sum of the dry air mass flow rates of the two induced draft branches reaches 0.80kg / s, and the dry air mass flow rate of each induced draft branch is not less than 0.35kg / s, and the above state is maintained for 5s, the controller 60 starts the first compressor 21; after the air temperature detected by the first temperature sensor 61 reaches 30℃, the controller 60 starts the second compressor 31. After the second compressor 31 has been running stably for 180s, the controller 60 adjusts the steam regulating valve 48 according to the detection result of the second temperature sensor 62, thereby avoiding the introduction of steam when the dry air mass flow rate is insufficient or the second heat pump system has not yet established a stable cycle.

[0094] Under rated operating conditions, the air temperature at the fresh air inlet 11 is 25℃, the relative humidity is 60%, and the dry air mass flow rate is 1.00 kg / s. Outside air enters the heating duct through the fresh air inlet 11, is first heated to 36℃ by the first condenser 22, then flows through the airflow channel 42 and is heated to 95℃ by the steam heat exchanger 40, and subsequently heated to 138℃ by the second condenser 32. The high-temperature air enters the first and second collection hoods 92 and 93 respectively from the first and second outlet areas 321 and 322 of the second condenser 32. It then forms two parallel flow paths through the first and second induced draft fans 90 and 91, and is further decelerated and diffused through the first and second guide branches 83 and 84, converged and equalized through the converging and equalizing section 85, and stratified and redirected through the curved air supply section 861. Finally, it enters the air distribution chamber 77 through the hot air outlet 12 and is evenly distributed into the air inlet side 701 of the drum 70 through each air distribution port.

[0095] The drum drive device 71 drives the drum 70 to rotate, causing the clothes to tumble continuously and come into full contact with the high-temperature air. Moisture in the clothes evaporates due to the heat and is discharged with the air from the air outlet 702 of the drum 70. The temperature of the humid air discharged from the drum 70 is approximately 72°C. After lint is removed by the lint filter 72, the humid air enters the waste heat recovery duct through the humid air inlet 13, first flowing through the second evaporator 34 and cooling to approximately 54°C, then flowing through the first evaporator 24 and cooling to approximately 45°C. The second evaporator 34 first recovers the higher-temperature waste heat, and the first evaporator 24 subsequently recovers the lower-temperature waste heat. When the humid air is cooled below the dew point temperature, the condensate is discharged through the condensate discharge device 73, and the cooled air is finally discharged by the exhaust fan 50 through the exhaust port 14.

[0096] When drying is complete or the equipment is shut down normally, controller 60 first closes steam regulating valve 48, then stops second compressor 31 and first compressor 21, and allows first induced draft fan 90, second induced draft fan 91 and exhaust fan 50 to continue running for 180 seconds; after heat dissipation is complete, controller 60 stops first induced draft fan 90, second induced draft fan 91 and exhaust fan 50. This shutdown sequence can dissipate residual heat in second condenser 32, steam supplementary heat exchanger 40, induced draft duct 80 and drum 70, reducing local heat accumulation after shutdown.

[0097] In this embodiment, high-temperature air from two outlet areas in the width direction of the second condenser 32 is collected by the first and second collector hoods 92 and 93, respectively. Two parallel flow paths are established by the independently speed-adjustable first and second guide fans 90 and 91. The two gradually expanding guide branches, the converging guide 87 with an arc-shaped guide surface, the flow equalization plate 88 with different porosities in each zone, and the arc-shaped deflecting guide vane 862 sequentially decelerate and diffuse the air, smooth the flow, equalize the flow laterally, and deflect it in layers. This reduces the lateral airflow difference on the outlet side of the second condenser 32 and the local eddies in the air supply section 86. The air distribution cavity 77 compensates for the pressure loss along the way by gradually increasing the total flow area of ​​the air distribution port in the direction away from the hot air outlet 12, and forms an axial and circumferential composite airflow through the air inlet guide vane, thereby improving the uniformity of air intake of the drum 70 and the uniformity of heating of the clothes. The controller 60 further implements branch balancing, temperature rise limitation and fault heat dissipation control based on the dry air mass flow rate of the two guide branches, which can reduce the operational risks caused by local overheating, air backflow and single fan failure while maintaining high temperature drying capacity.

[0098] Example 2

[0099] Combination Figure 14This embodiment is basically the same as Embodiment 1 in terms of structure and control principle, except that: the first condenser 22, the second condenser 32, and the steam supplementary heat exchanger 40 are all located on the top of the casing 10 and are arranged sequentially from the front to the rear of the casing 10 along the air flow direction in the heating air duct; the air inlet side of the first condenser 22 is connected to the fresh air inlet 11, the air outlet side of the first condenser 22 is sealed and connected to the air inlet side of the second condenser 32, and the air outlet side of the second condenser 32 is connected to the air inlet of the air flow duct 42. End 421 is sealed and connected, and the air outlet 422 of the airflow channel 42 is connected to the air inlet side of the first induced draft fan 90 and the second induced draft fan 91 respectively; the first guide inlet 81 and the second guide inlet 82 are located downstream of the steam supplementary heat exchanger 40 along the airflow direction, and the first induced draft fan 90 and the second induced draft fan 91 are respectively arranged between the steam supplementary heat exchanger 40 and the corresponding guide inlet to form two parallel induced draft paths from the air outlet 422 of the airflow channel 42 into the guide airflow channel 80. In this embodiment, the steam supplementary heat exchanger 40 constitutes the final stage heating component. The first temperature sensor 61, the third temperature sensor 63, and the second temperature sensor 62 sequentially detect the outlet air temperature of the first condenser 22, the second condenser 32, and the airflow channel 42 along the airflow direction. The corresponding target air temperatures are set to 36℃, 95℃, and 138℃ respectively. The controller 60 adjusts the operating frequency of the first compressor 21, the operating frequency of the second compressor 31, and the opening degree of the steam regulating valve 48 according to the corresponding detection results. The remaining structure, parameters, and fault heat dissipation control are the same as in Embodiment 1. This arrangement first uses the first heat pump system and the second heat pump system to perform staged heating of the fresh air, and then uses the steam supplementary heat exchanger 40 for final stage supplementary heating to adapt to different external steam conditions and target supply air temperatures. In other embodiments, the first condenser 22, the second condenser 32 and the steam supplement heat exchanger 40 may also be arranged in other locations within the casing 10 that can form a heating air duct, and are not limited to being arranged at the top of the casing 10. As long as the three are arranged in series along the air flow path in the heating air duct, and the first condenser 22 is located upstream of the second condenser 32 and the air flow duct 42.

[0100] It should be noted that, unless the context explicitly defines otherwise, the terms "first," "second," etc., used in this specification and claims are only used to distinguish technical features with the same name or similar functions, and should not be construed as an automatic limitation on their order, quantity, or importance. For the airflow sequence, heat exchange sequence, temperature level relationship, and control sequence explicitly defined in this invention, they should be understood according to the corresponding technical content. The terms "upper," "lower," "inner," "outer," "front," "rear," etc., used in this specification, refer to the accompanying drawings and the normal operating state of the industrial drum dryer, and are only used to simplify the description and facilitate understanding of the relative positional relationships between related technical features. Unless explicitly defined otherwise, they do not constitute a limitation on the actual installation direction of the dual-path flow equalizing pressure air supply heat pump waste heat recovery system and the industrial drum dryer.

[0101] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to exhaustively describe or limit the scope of protection of the present invention. Where there is no conflict, the technical features of the above embodiments and other embodiments can be combined with each other. Equivalent substitutions, simple modifications, or conventional adjustments made by those skilled in the art based on the disclosure of this specification without departing from the concept of the present invention should all fall within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A dual-path pressure equalization air-supply heat pump waste heat recovery system, comprising a casing, a first heat pump system, a second heat pump system, a steam heat exchanger, and an exhaust fan, wherein the first heat pump system comprises a first compressor, a first condenser, a first throttling device, and a first evaporator connected in sequence to form a first refrigerant circulation loop, and the second heat pump system comprises a second compressor, a second condenser, a second throttling device, and a second evaporator connected in sequence to form a second refrigerant circulation loop; a heating duct connecting a fresh air inlet and a hot air outlet, and a waste heat recovery duct connecting a humid air inlet and an exhaust outlet are formed within the casing, wherein the second evaporator, the first evaporator, and the exhaust fan are arranged sequentially along the airflow direction within the waste heat recovery duct; when the first heat pump system and the second heat pump system operate simultaneously, the evaporation saturation temperature and the condensation saturation temperature of the second heat pump system are respectively higher than the evaporation saturation temperature and the condensation saturation temperature of the first heat pump system, characterized in that: The steam reheating heat exchanger has a steam flow channel and an air flow channel that are isolated from each other and exchange heat. The steam flow channel is provided with a steam inlet for communicating with an external steam source. Along the airflow direction within the heating duct, the first condenser, the second condenser, and the airflow duct are connected in series. The air inlet side of the first condenser is connected to the fresh air inlet and is located upstream of the second condenser and the airflow duct. The downstream one of the second condenser and the airflow duct constitutes the final stage heating component. The dual-path induced flow equalization and air supply heat pump waste heat recovery system further includes an induced flow duct, a first induced flow fan, and a second induced flow fan. The induced flow duct includes a first induced flow inlet, a second induced flow inlet, a first induced flow branch, a second induced flow branch, a convergence equalization section, and an air supply section. The first induced flow branch and the second induced flow branch are respectively connected to the corresponding induced flow inlet and the convergence equalization section, and the convergence equalization section is connected to the air supply section. The first guide inlet and the second guide inlet are both located on the top of the housing and downstream of the final stage heating component; the first duct fan and the second duct fan are respectively located between the final stage heating component and the corresponding guide inlet, and the air inlets are all facing the air outlet side of the final stage heating component, and the air outlets are respectively connected to the corresponding guide inlets to form two parallel ducting paths; The air supply section extends from the confluence and equalization section to the front of the casing, and the outlet of the air supply section constitutes the hot air outlet; The airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component. The air outlet side of the second condenser is divided into a first air outlet area and a second air outlet area along the width direction of the second condenser. The first and second induced draft fans are spaced apart along the width direction of the second condenser and correspond to the first and second air outlet areas, respectively. The air outlet side of the second condenser is provided with a first and a second induced draft hood, respectively covering the first and second air outlet areas. Both the first and second induced draft hoods have an inlet facing the second condenser and a constricted outlet facing the corresponding induced draft fan, and the flow cross-sectional area gradually decreases from the inlet to the constricted outlet. The inlet of the first induced draft fan is sealed and connected to the constricted outlet of the first induced draft hood, and the inlet of the second induced draft fan is sealed and connected to the constricted outlet of the second induced draft hood.

2. The dual-path flow equalizing air supply heat pump waste heat recovery system according to claim 1, characterized in that: The housing has a longitudinal intermediate surface extending along its front-rear direction. The first and second flow guide branches are located on both sides of the longitudinal intermediate surface and extend from the rear to the front of the housing. The flow cross-sectional areas of the first and second flow guide branches gradually increase along the airflow direction. The effective flow cross-sectional area of ​​the converging and equalizing section at the junction with the first and second flow guide branches is not less than the sum of the effective flow cross-sectional areas of the first and second flow guide branches at their corresponding junctions. The converging and equalizing section is provided with a converging guide member located between the first and second flow guide branches. The converging guide member has two arc-shaped flow guide surfaces facing the first and second flow guide branches respectively. The two arc-shaped flow guide surfaces are smoothly connected to the inner walls of the corresponding flow guide branches. The converging guide member gradually narrows from its upstream end to its downstream end so that the two streams of air converge into the air supply section in the same direction.

3. The dual-path flow equalizing air supply heat pump waste heat recovery system according to claim 2, characterized in that: The air supply section includes a curved air supply section for changing the airflow direction. The curved air supply section is provided with multiple spaced arc-shaped deflector vanes. The tangent direction of the upstream end of each arc-shaped deflector vane is consistent with the airflow direction in the converging and equalizing section, and the tangent direction of the downstream end of each arc-shaped deflector vane is consistent with the airflow direction of the hot air outlet, so as to stratify and deflect the air after it has been converged in the converging and equalizing section and deliver it to the hot air outlet.

4. The dual-path flow equalizing air supply heat pump waste heat recovery system according to claim 2, characterized in that: The flow equalization section is provided with a flow equalization plate spanning the flow equalization section on the downstream side of the flow guide. The flow equalization plate is provided with a plurality of ventilation holes. The flow equalization plate includes a windward area opposite to the air outlet direction of the first flow guide branch and the second flow guide branch, respectively, and a compensation area located outside each windward area. The porosity of the windward area is less than that of the compensation area.

5. The dual-path flow equalizing air supply heat pump waste heat recovery system according to claim 1, characterized in that: The first and second diversion branches are respectively equipped with a first branch main air mass flow rate detector and a second branch main air mass flow rate detector. Both the first and second diversion fans are variable frequency fans with independently adjustable speeds. The dual-path diversion equalizing air supply heat pump waste heat recovery system also includes a controller. The first branch main air mass flow rate detector, the second branch main air mass flow rate detector, the first diversion fan, and the second diversion fan are electrically connected to the controller. The controller independently adjusts the operating frequency of the first and second diversion fans according to the detection results of the first and second branch main air mass flow rate detectors to change the speed of the first and second diversion fans, so that the difference in dry air mass flow rate between the first and second diversion branches is within a preset branch flow rate balance range, and the sum of the dry air mass flow rates of the two diversion branches reaches a preset total dry air mass flow rate.

6. The dual-path flow equalizing air supply heat pump waste heat recovery system according to claim 5, characterized in that: The airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component. The heating airflow channel is equipped with a first temperature sensor, a second temperature sensor, and a third temperature sensor to detect the air temperature at the outlet of the first condenser, the air temperature at the outlet of the airflow channel, and the air temperature at the outlet of the second condenser, respectively. The steam inlet is equipped with a steam regulating valve. Both the first compressor and the second compressor are variable frequency compressors with adjustable operating frequencies. The first temperature sensor, the second temperature sensor, the third temperature sensor, the steam regulating valve, the first compressor, and the second compressor are all electrically connected to the controller. In high-temperature drying mode, the controller adjusts the operating frequency of the first compressor, the opening degree of the steam regulating valve, and the [other parameters] based on the detection results of the first temperature sensor, the second temperature sensor, and the third temperature sensor, respectively. The operating frequency of the second compressor is adjusted so that the air temperature at the outlet of the airflow channel is higher than the air temperature at the outlet of the first condenser, and the air temperature at the outlet of the second condenser is higher than the air temperature at the outlet of the airflow channel. When the difference in dry air mass flow rate between the two guide branches exceeds the preset branch flow rate balance range, the controller preferentially adjusts the operating frequencies of the first and second guide fans to change their speeds. Before the difference in dry air mass flow rate between the two guide branches returns to the preset branch flow rate balance range, the controller restricts the steam regulating valve from increasing its opening and restricts the second compressor from increasing its operating frequency. When the sum of the dry air mass flow rates of the two guide branches is lower than the preset safe dry air mass flow rate, the controller closes the steam regulating valve and controls the first and second compressors to reduce their operating frequencies or stop operating.

7. An industrial drum dryer, comprising a casing, a drum, a drum drive device, a first heat pump system, a second heat pump system, a steam heat exchanger, an exhaust fan, and a lint filter. The drum is rotatably disposed within the casing. The drum drive device is connected to the drum for driving the drum to rotate. The casing has a fresh air inlet and an exhaust outlet. The casing has a clothes loading / unloading opening corresponding to the drum. The drum has an air inlet side and an air outlet side, with the air inlet side located near the clothes loading / unloading opening. The first heat pump system includes a first compressor, a first condenser, a first throttling device, and a first evaporator connected sequentially in a first refrigerant circulation loop via refrigerant piping. The second heat pump system includes a second compressor, a second condenser, a second throttling device, and a second evaporator connected sequentially in a second refrigerant circulation loop via refrigerant piping. The steam heat exchanger has a steam channel and an air channel that are isolated from each other and exchange heat. The steam channel has a steam inlet for communicating with an external steam source. The first condenser, the second condenser, and the air flow channel are connected in series. The air inlet side of the first condenser is connected to the fresh air inlet and is located upstream of the second condenser and the air flow channel. The downstream one of the second condenser and the air flow channel constitutes the final stage heating component. When the first heat pump system and the second heat pump system are operating simultaneously, the evaporation saturation temperature and condensation saturation temperature of the second heat pump system are respectively higher than the evaporation saturation temperature and condensation saturation temperature of the first heat pump system, characterized in that: The first condenser, the steam reheating heat exchanger, and the second condenser are all located on the top of the casing and arranged sequentially from front to back along the front-to-back direction of the casing. The industrial drum dryer also includes a guide air duct, a first induced draft fan, and a second induced draft fan. The guide air duct includes a first guide inlet and a second guide inlet located on the top of the casing and behind the second condenser, a first guide branch connected to the first guide inlet, a second guide branch connected to the second guide inlet, a convergence and equalization section connected to the two guide branches respectively, and an air supply section extending from the convergence and equalization section to the front of the casing. The outlet of the air supply section is connected to the air inlet side of the drum. The first induced draft fan and the second induced draft fan are... The air inlets of each of the induced draft fans are positioned between the second condenser and the corresponding guide inlet. Each induced draft fan's air inlet faces the air outlet of the second condenser, and each induced draft fan's air outlet is connected to its corresponding guide inlet, forming two parallel induced draft paths from the air outlet of the second condenser into the guide air duct. A through-type air passage is formed within the casing. Along the airflow direction within the through-type air passage, the fresh air inlet, the first condenser, the air duct, the second condenser, the two parallel induced draft paths, the guide air duct, the air inlet side of the drum, the air outlet side of the drum, the lint filter, the second evaporator, the first evaporator, the exhaust fan, and the exhaust outlet are sequentially connected. The airflow channel is located between the first condenser and the second condenser, with the second condenser constituting the final stage heating component. The air outlet side of the second condenser is divided into a first air outlet area and a second air outlet area along the width direction of the second condenser. The first and second induced draft fans are spaced apart along the width direction of the second condenser and correspond to the first and second air outlet areas, respectively. The air outlet side of the second condenser is provided with a first and a second induced draft hood, respectively covering the first and second air outlet areas. Both the first and second induced draft hoods have an inlet facing the second condenser and a constricted outlet facing the corresponding induced draft fan, and the flow cross-sectional area gradually decreases from the inlet to the constricted outlet. The inlet of the first induced draft fan is sealed and connected to the constricted outlet of the first induced draft hood, and the inlet of the second induced draft fan is sealed and connected to the constricted outlet of the second induced draft hood.

8. The industrial drum dryer according to claim 7, characterized in that: The air inlet side of the roller is provided with an air distribution chamber, which at least partially surrounds the outer periphery of the clothing loading and unloading opening. The outlet of the air supply section is connected to the air distribution chamber. The air distribution chamber is provided with a plurality of air outlets facing the inner cavity of the roller along its extension direction. The air distribution chamber is divided into a plurality of equal-length sections along its extension direction. Along the direction away from the outlet of the air supply section, the total flow area of ​​the air outlets in each of the equal-length sections gradually increases. Each air outlet is provided with an air inlet guide plate, which makes the air entering the inner cavity of the roller have both a velocity component along the axial direction of the roller and a velocity component along the circumferential direction of the roller.

9. The industrial drum dryer according to claim 7, characterized in that: A check valve is provided between the outlet of the first induced draft fan and the first guide inlet, and between the outlet of the second induced draft fan and the second guide inlet, respectively, to allow air to flow only towards the guide duct; a steam regulating valve is provided at the steam inlet; the industrial drum dryer also includes a controller; both the first compressor and the second compressor are variable frequency compressors with adjustable operating frequencies; the first induced draft fan is equipped with a first fan operating status detection device, and the second induced draft fan is equipped with a second fan operating status detection device; a first branch air mass flow rate detection device and a second branch air mass flow rate detection device are respectively provided in the first guide branch and the second guide branch; the first fan operating status detection device and the second fan operating status detection device... The first branch dry air mass flow rate detection device, the second branch dry air mass flow rate detection device, the first induced draft fan, the second induced draft fan, the steam regulating valve, the first compressor, the second compressor, and the exhaust fan are all electrically connected to the controller. When the first fan operation status detection device or the second fan operation status detection device detects that the corresponding induced draft fan has malfunctioned, or when the dry air mass flow rate of any induced draft branch is lower than the preset minimum dry air mass flow rate of the branch for a preset time, the controller closes the steam regulating valve, controls the first compressor and the second compressor to reduce their operating frequency or stop operating, and allows the induced draft fan and the exhaust fan, which are in normal operating condition, to continue operating for a preset heat dissipation time.

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