A closed condensate recovery device

Abstract

This invention relates to the field of condensate recovery technology, specifically a closed-loop condensate recovery device, comprising a tank with a water outlet pipe at the bottom. The tank is divided into three zones—a central steam buffer zone, a lower condensate collection zone, and an upper negative pressure condensation zone—by two horizontal baffles. This closed-loop condensate recovery device eliminates the need for additional power components such as pumps. It relies on the downward pressure difference of the condensate in the negative pressure condensation zone and the negative pressure generated by steam condensation as the drainage driving force. It fully utilizes the system's own energy, eliminating dependence on external power and significantly reducing operating energy consumption. The condensate introduced by the downward pressure drainage pipe creates a downward impact, which, combined with the negative pressure introduced by the negative pressure venting pipe, forms a dual drainage drive, providing stronger power and higher efficiency than traditional single gravity drainage. Simultaneously, it drives the condensate in the pipe to repeatedly flush, comprehensively covering the entire pipe area and thoroughly removing impurities and silt from different sections, offering better anti-clogging performance than unidirectional disturbance.

Description

Technical Field

[0001] This invention relates to the field of condensate recovery technology, specifically a closed-loop condensate recovery device. Background Technology

[0002] In steam heating systems for industrial production and civil buildings, steam releases heat through heat exchange equipment and condenses to form high-temperature condensate. This condensate is not only clean but also contains a large amount of recoverable heat energy, making it a highly valuable secondary resource. Therefore, the efficient recovery and reuse of condensate is of great significance for conserving water resources, reducing energy consumption, and improving the economic efficiency of system operation.

[0003] Currently, condensate recovery systems are mainly divided into two types: open-loop and closed-loop. Traditional open-loop recovery systems collect condensate through open tanks, which has several prominent problems: First, the high-temperature condensate comes into direct contact with the air, generating a large amount of secondary flash vapor, resulting in the loss of heat energy and softened water, leading to serious waste of energy and water resources. Second, gases such as oxygen and carbon dioxide in the air easily dissolve in the condensate, forming corrosive media that cause severe oxygen corrosion to downstream pipelines and equipment, significantly shortening equipment lifespan. Furthermore, the recovered water needs to be purified again, increasing operating costs and environmental pressure.

[0004] To address the drawbacks of open-loop condensate recovery systems, closed-loop condensate recovery systems have been gradually adopted. However, existing closed-loop condensate recovery devices still face several technical bottlenecks: First, the dynamic characteristics of the coexistence of steam and water phases within the system easily lead to steam blockage and water hammer, affecting drainage smoothness. Second, the recovery of condensate under different pressure conditions is difficult, with low-pressure condensate often experiencing problems such as poor return flow and insufficient rise time. Third, increased back pressure after the steam trap reduces drainage capacity; if individual steam traps leak severely, it can lead to abnormal back pressure in the entire system, affecting normal equipment operation. Fourth, centrifugal pumps are prone to cavitation when transporting high-temperature condensate, severely affecting transport stability and equipment lifespan. Furthermore, some closed-loop devices suffer from complex structures, low automation levels, and pipeline blockage due to impurities, limiting their widespread application under various operating conditions.

[0005] In view of this, we propose a closed-loop condensate recovery device. Summary of the Invention

[0006] The purpose of this invention is to provide a closed-loop condensate recovery device to solve the problems mentioned in the background art, such as steam blockage and water hammer, poor water return, significant influence of back pressure on drainage capacity, easy cavitation of centrifugal pumps, easy pipe blockage, and low degree of automation in existing closed-loop recovery devices. To achieve the above objective, this invention provides the following technical solution: a closed-loop condensate recovery device, comprising a tank with a water outlet pipe at the bottom.

[0007] The tank body is divided into three zones: a central steam buffer zone, a lower condensate collection zone, and an upper negative pressure condensation zone, by two horizontal partitions.

[0008] The partition in the middle is a sieve plate with vent holes, and its edges are sealed to the inner wall of the tank.

[0009] The upper partition is a fully sealed plate, with a steam guide pipe on the upper side of the plate, and a one-way valve installed inside the pipe that only allows steam to pass through from bottom to top.

[0010] One end of the steam input pipe is connected to an external steam source, and the other end is connected to the steam buffer zone radially along the tank body.

[0011] The negative pressure condensation zone is equipped with a condensation coil and a liquid level sensor. The condensation coil is a spiral structure that fits into the inner wall of the tank. Cooling water flows through the coil and is connected to the external cooling water circulation system. The liquid level sensor is a float type and is used to monitor the condensate level in real time.

[0012] The tank is equipped with a condensate drain pipe. One end of the condensate drain pipe is connected to the negative pressure condensation zone, and the other end passes through the middle partition, the tank body, and the water outlet pipe at the bottom.

[0013] An electric ball valve is installed on the drainage pipe, and the electric ball valve is electrically connected to the liquid level sensor.

[0014] Preferably, a negative pressure air guide pipe is provided on one side of the tank, with one end connected to the negative pressure condensation zone and the other end connected to the end of the water outlet pipe.

[0015] An intermittent control valve is installed on the negative pressure air duct. The intermittent control valve is an electromagnetic pulse valve and is installed at the end of the negative pressure air duct near the water outlet pipe.

[0016] A pressure sensor is installed on the negative pressure air duct, at the end of the negative pressure air duct near the negative pressure condensation zone, to provide feedback on the negative pressure signal.

[0017] Preferably, a three-way valve is provided at the bottom of the negative pressure air guide pipe. The two outlets of the three-way valve are respectively connected to the beginning and end of the water outlet pipe. The three-way valve is a solenoid valve, which is synchronously linked with the intermittent control valve to realize the alternating switching of negative pressure at the beginning and end of the water outlet pipe.

[0018] Preferably, a check valve is installed on the water outlet pipe.

[0019] Preferably, a control mechanism is provided outside the tank body. The control mechanism adopts a PLC controller and is electrically connected to the liquid level sensor, pressure sensor, electric ball valve, and intermittent control valve respectively.

[0020] Preferably, the condenser coil is connected to the external cooling water circulation system via a flange connection.

[0021] Preferably, a flow guide joint is provided at the connection between the flow diversion pipe and the water outlet pipe, and the flow guide joint is inclined toward the end of the water outlet pipe.

[0022] Preferably, the drainage pipe is a polyurethane heat-insulated pipe.

[0023] A method for using a closed-loop condensate recovery device includes the following steps:

[0024] S1. External steam enters the steam buffer zone in the middle of the tank through the steam input pipe along the radial direction of the tank body. Two horizontal baffles in the tank body effectively isolate the steam buffer zone, the lower condensate collection zone, and the upper negative pressure condensation zone, ensuring that each area functions independently.

[0025] S2. During the diffusion process of steam in the steam buffer zone, some steam condenses into liquid water after contacting the tank wall and the middle baffle. The liquid water drips down along the edge of the sieve plate and the inner wall of the tank, and finally flows into the lower condensate collection area.

[0026] S3. Uncondensed steam flows upward through the middle baffle and enters the negative pressure condensation zone via the steam guide pipe on the upper part of the upper baffle and the one-way valve inside the pipe. Cooling water is introduced into the spiral condensing coil in the negative pressure condensation zone. Under the cooling effect of the cooling water, the steam quickly condenses into liquid water. As the steam continues to condense, a stable negative pressure gradually forms in the negative pressure condensation zone.

[0027] S4. The liquid level sensor monitors the condensate level in the negative pressure condensation zone in real time. When the liquid level reaches the set threshold, the sensor sends a signal to the electric ball valve, which then opens. The condensate in the negative pressure condensation zone flows into the outlet pipe through the downward pressure drainage pipe, which in turn propels the condensate in the condensate collection area, driving the condensate to be discharged along the outlet pipe.

[0028] S5. When the condensate level in the negative pressure condensing zone drops to the set lower limit, the level sensor sends a signal to the electric ball valve, the electric ball valve closes, and the negative pressure condensing zone starts accumulating condensate again.

[0029] S6. The electromagnetic pulse valve installed at the end of the negative pressure venting pipe near the water outlet pipe opens periodically at a set frequency, guiding the negative pressure from the negative pressure condensation zone to the end of the water outlet pipe. This enhances drainage power while preventing impurities from accumulating in the pipe through negative pressure disturbance. A pressure sensor monitors the negative pressure signal in real time and feeds it back to the control mechanism to ensure stable negative pressure.

[0030] S7, the three-way valve and the intermittent control valve work in sync for a timed start, alternately introducing negative pressure into the beginning and end of the outlet pipe. Under the alternating negative pressure, the condensate in the pipe is driven to form a reciprocating flushing flow, thoroughly removing impurities from different sections of the pipe and further improving the anti-clogging effect.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. High energy utilization and low energy consumption: No additional power components such as pumps are required. The core relies on the drop pressure difference of the condensate in the negative pressure condensation zone and the negative pressure formed by steam condensation as the driving force for drainage. It makes full use of the system's own energy, gets rid of dependence on external power, and significantly reduces operating energy consumption.

[0033] 2. High drainage efficiency and thorough anti-clogging effect: The condensate introduced by the downward flow pipe forms a downward impact, which, together with the negative pressure introduced by the negative pressure vent pipe, forms a dual drainage drive, which is more powerful and efficient than the traditional single gravity drainage. At the same time, through the combination design of intermittent negative pressure + three-way valve alternating introduction, the condensate in the pipe is driven to flush back and forth, which can fully cover the entire pipe area and thoroughly remove the impurities and siltation in different sections. The anti-clogging effect is better than that of single-direction disturbance.

[0034] 3. Stable operation and convenient maintenance: The three zones are effectively isolated by two horizontal partitions. With the one-way valve in the upper steam guide hole, condensate backflow can be prevented, ensuring the stable function of each zone. The core components are all conventional standardized components with a compact layout and clear zoning. They are easy to install and replace, have low subsequent maintenance costs, and can be adjusted by the control mechanism to adapt to different working conditions. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 1 ;

[0036] Figure 2 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 2 ;

[0037] Figure 3 A three-dimensional cross-sectional view of the tank body of the present invention. Figure 1 ;

[0038] Figure 4 A three-dimensional cross-sectional view of the tank body of the present invention. Figure 2 ;

[0039] Figure 5 A three-dimensional cross-sectional view of the tank body of the present invention. Figure 3 ;

[0040] Figure 6 For the present invention Figure 5 Enlarged view of point A in the middle;

[0041] Figure 7 This is a three-dimensional structural cross-sectional view of the present invention;

[0042] Figure 8 For the present invention Figure 7 Enlarged view of point B in the middle.

[0043] In the diagram: 1. Outlet pipe; 2. Tank; 3. Baffle; 4. Steam buffer zone; 5. Condensate collection zone; 6. Negative pressure condensate zone; 7. Steam guide pipe; 8. Check valve; 9. Steam input pipe; 10. Condensate coil; 11. Liquid level sensor; 12. Downward pressure drain pipe; 13. Electric ball valve; 14. Negative pressure vent pipe; 15. Intermittent control valve; 16. Pressure sensor; 17. Three-way valve. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Please see Figures 1 to 8 This invention provides a technical solution: a closed condensate recovery device, including a tank 2 with a water outlet pipe 1 at the bottom, and a recovery water tank or reuse pipeline connected to the end of the water outlet pipe 1, to realize the centralized recovery and reuse of clean condensate, effectively saving water resources. The tank 2 is an integral closed structure, and the top and side walls of the tank 2 are all sealed with no additional openings, only reserved for connection interfaces with external pipes, so as to ensure the airtightness of each area inside the tank 2, prevent outside air from entering and disrupting the negative pressure environment, and at the same time avoid the leakage of steam inside the tank 2, which would cause energy loss.

[0046] Inside the tank 2, two horizontal baffles 3 separate the steam buffer zone 4 in the middle, the condensate collection zone 5 in the lower part, and the negative pressure condensation zone 6 in the upper part. Through the structural design of the three-zone isolation, the steam condensation process and the condensate collection and discharge process can be carried out independently in different areas, avoiding mutual interference between the operating conditions of different areas and ensuring the stability of the equipment operation.

[0047] The central partition 3 is a sieve plate with vents, and its edge is sealed to the inner wall of the tank 2. The sealing connection between the partition 3 and the inner wall of the tank 2 is reinforced and sealed with a sealing ring to ensure that steam can only flow between the steam buffer zone 4 and the condensate collection zone 5 through the vents of the sieve plate, without any leakage of condensate or air. The size and distribution of the vents of the sieve plate can meet the requirement of smooth upward flow of uncondensed steam, and at the same time, it can play a certain role in guiding the falling condensate. The sealed connection design can prevent condensate from leaking between areas and ensure the independence of each area.

[0048] The upper partition 3 is a fully sealed plate with a steam guide pipe 7 on the upper side. A one-way valve 8 is installed inside the pipe, which only allows steam to pass from bottom to top. The fully sealed plate can completely isolate the direct connection between the steam buffer zone 4 and the negative pressure condensing zone 6, so that uncondensed steam can only enter the negative pressure condensing zone 6 through the steam guide pipe 7. The one-way valve 8 can effectively prevent the condensate in the negative pressure condensing zone 6 from flowing back to the steam buffer zone 4, and at the same time avoid the negative pressure environment of the negative pressure condensing zone 6 from being damaged.

[0049] One end of the steam input pipe 9 is connected to an external steam source, and the other end is radially connected to the steam buffer zone 4 along the tank body 2. The connection between the steam input pipe 9 and the tank body 2 is sealed by welding or flange to prevent steam from leaking out from the connection gap and to ensure that all steam enters the steam buffer zone 4 to participate in the condensation process. The radial connection allows the external steam to quickly diffuse to the surroundings after entering the steam buffer zone 4, increasing the contact area between the steam and the wall of the tank body 2 and the middle baffle 3, thereby improving the efficiency of the initial condensation.

[0050] The negative pressure condensation zone 6 is equipped with a condensing coil 10 and a liquid level sensor 11. The condensing coil 10 is a spiral structure installed close to the inner wall of the tank 2. Cooling water is introduced into the coil and connected to an external cooling water circulation system. The liquid level sensor 11 is a float type, used to monitor the condensate level in real time. The spiral structure of the condensing coil 10, installed close to the inner wall of the tank 2, can maximize the use of the inner wall space of the tank 2, increase the contact area between the condensing coil 10 and the steam, and improve the steam condensation efficiency. The external cooling water circulation system can continuously provide low-temperature cooling water to the condensing coil 10 to ensure the stability of the condensation effect. The float-type liquid level sensor 11 can provide real-time feedback of the liquid level signal according to the change of the condensate level, providing precise control basis for the opening and closing of the electric ball valve 13.

[0051] A downward flow pipe 12 is installed inside the tank body 2. One end of the downward flow pipe 12 is connected to the negative pressure condensation zone 6, and the other end passes through the middle partition 3, the tank body 2, and connects to the bottom water outlet pipe 1. Sealing sleeves are installed at the positions where the downward flow pipe 12 passes through the middle partition 3 and the wall of the tank body 2. The sealing sleeves are welded and sealed or compacted with sealing filler between themselves and the partition 3 and the wall of the tank body 2 to ensure that the sealing of the tank body 2 is not affected by the pipe. The layout path of the downward flow pipe 12 can make full use of the height difference between the negative pressure condensation zone 6 and the water outlet pipe 1 to provide sufficient downward force for the condensate. The position where it passes through the middle partition 3 is sealed to prevent steam or condensate leakage.

[0052] An electric ball valve 13 is installed on the drainage pipe 12. The electric ball valve 13 is electrically connected to the liquid level sensor 11. Through the electrical connection, the liquid level sensor 11 can transmit the monitored liquid level signal to the electric ball valve 13 in real time, realizing the automatic opening and closing control of the electric ball valve 13 without manual intervention.

[0053] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, a negative pressure venting pipe 14 is installed on one side of the tank body 2. One end is connected to the negative pressure condensation zone 6, and the other end is connected to the end of the water outlet pipe 1. The negative pressure venting pipe 14 can introduce the negative pressure of the negative pressure condensation zone 6 into the end of the water outlet pipe 1 to form a negative pressure suction effect. Combined with the downward thrust of the downward flow pipe 12, it further improves the discharge efficiency of condensate.

[0054] An intermittent control valve 15 is installed on the negative pressure vent pipe 14. The intermittent control valve 15 is an electromagnetic pulse valve and is installed at the end of the negative pressure vent pipe 14 near the water outlet pipe 1. A pressure sensor 16 is installed on the negative pressure vent pipe 14 at the end of the negative pressure vent pipe 14 near the negative pressure condensation zone 6 to provide feedback on the negative pressure signal. The electromagnetic pulse valve can periodically open and close according to a set frequency to realize the intermittent introduction of negative pressure. The pressure sensor 16 can monitor the negative pressure value of the negative pressure condensation zone 6 in real time and feed the signal back to the control mechanism, so that the control mechanism can adjust the opening and closing frequency of the intermittent control valve 15 according to the negative pressure situation to ensure the stability of the negative pressure environment.

[0055] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, a three-way valve 17 is installed on the negative pressure vent pipe 14. The two outlets of the three-way valve 17 are connected to the beginning and end of the water outlet pipe 1, respectively. The three-way valve 17 is a solenoid valve, which is synchronously linked with the intermittent control valve 15 to realize the alternating switching of negative pressure at the beginning and end of the water outlet pipe 1. The synchronous linkage between the three-way valve 17 and the intermittent control valve 15 enables the negative pressure to act alternately on both ends of the water outlet pipe 1, driving the condensate in the pipe to form a reciprocating flushing water flow, thereby thoroughly cleaning the impurities attached to the inner wall of the pipe and avoiding long-term accumulation of impurities that could cause pipe blockage.

[0056] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, a check valve is installed on the water outlet pipe 1. The check valve can effectively prevent the condensate in the water outlet pipe 1 from flowing back, and avoid the condensate from flowing back to the condensate collection area 5 or the negative pressure condensation area 6, thus ensuring the normal operation of the device.

[0057] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8As shown, a control mechanism is installed outside the tank 2. The control mechanism adopts a PLC controller, which is electrically connected to the liquid level sensor 11, pressure sensor 16, electric ball valve 13, and intermittent control valve 15 respectively to realize automatic regulation. The PLC controller can receive the signals fed back by the liquid level sensor 11 and pressure sensor 16, and accurately control the opening and closing of the electric ball valve 13 and intermittent control valve 15 according to the preset program logic, so as to realize the fully automatic operation of the device, reduce the intensity of manual operation, and improve the operating efficiency.

[0058] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, the condenser coil 10 is connected to the external cooling water circulation system by a flange connection. A sealing gasket is installed at the flange connection to ensure that there is no leakage during the cooling water circulation process. At the same time, it prevents outside air from entering the negative pressure condensation zone 6 through the connection port, maintaining the closed operation state of the tank 2. The flange connection has the advantages of strong connection, good sealing performance and convenient disassembly and assembly, which facilitates the installation, maintenance and replacement of the condenser coil 10.

[0059] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, a guide joint is provided at the connection between the drain pipe 12 and the outlet pipe 1, and the guide joint is inclined toward the end of the outlet pipe 1. The inclined guide joint can guide the condensate discharged from the drain pipe 12, so that the condensate can flow smoothly into the outlet pipe 1, avoid the condensate from stagnating at the connection, reduce the water flow resistance, and improve the drainage efficiency.

[0060] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 8 As shown, the sinking drainage pipe 12 is a polyurethane heat insulation pipe. The polyurethane heat insulation pipe has good heat insulation performance and can effectively block the heat from the lower condensate collection area 5 from being transferred into the sinking drainage pipe 12, preventing the condensate in the drainage pipe from evaporating again due to heat absorption and temperature rise, preventing the gas generated by evaporation from entering the negative pressure condensation area 6 and destroying the negative pressure environment, thus ensuring the stability of the negative pressure condensation effect.

[0061] A method for using a closed-loop condensate recovery device includes the following steps:

[0062] S1. External steam enters the central steam buffer zone 4 inside the tank 2 radially through the steam input pipe 9. The two horizontal baffles 3 inside the tank 2 effectively isolate the steam buffer zone 4, the lower condensate collection zone 5, and the upper negative pressure condensation zone 6, ensuring that each area functions independently. After the steam enters the steam buffer zone 4 radially, it can quickly diffuse to the entire area, preparing for subsequent preliminary condensation.

[0063] S2. During the diffusion of steam in the steam buffer zone 4, some steam condenses into liquid water after contacting the wall of tank 2 and the middle partition 3. The liquid water drips along the edge of the sieve plate and the inner wall of tank 2, and finally flows into the lower condensate collection area 5. After the steam comes into contact with the low temperature wall of tank 2 and the middle partition 3, it releases heat and undergoes a phase change to form condensate. Under the action of gravity, it falls naturally and is collected.

[0064] S3. Uncondensed steam flows upward through the middle partition 3, and enters the negative pressure condensation zone 6 through the steam guide pipe 7 on the upper side of the upper partition 3 and the one-way valve 8 inside the pipe. Cooling water is introduced into the spiral condensing coil 10 in the negative pressure condensation zone 6. Under the cooling effect of the cooling water, the steam quickly condenses into liquid water. As the steam continues to condense, a stable negative pressure gradually forms in the negative pressure condensation zone 6. Uncondensed steam flows upward through the vent holes of the sieve plate, and after entering the negative pressure condensation zone 6 through the steam guide pipe 7 and the one-way valve 8, it comes into full contact with the low temperature condensing coil 10 and quickly completes the condensation process. As the steam continues to condense, the number of gas molecules in the negative pressure condensation zone 6 decreases, and a stable negative pressure environment gradually forms.

[0065] S4. The liquid level sensor 11 monitors the condensate level in the negative pressure condensation zone 6 in real time. When the liquid level reaches the set threshold, the sensor sends a signal to the electric ball valve 13, which then opens. The condensate in the negative pressure condensation zone 6 flows into the outlet pipe 1 through the downward flow pipe 12 under the action of the downward flow difference, which boosts the condensate in the condensate collection zone 5 and drives the condensate to be discharged along the outlet pipe 1. When the condensate level reaches the set threshold, the electric ball valve 13 automatically opens, and the condensate flows rapidly under the action of the downward flow caused by the height difference. When it flows into the outlet pipe 1, it can generate a thrust on the condensate in the collection zone, accelerating the overall drainage speed.

[0066] S5. When the condensate level in the negative pressure condensing zone 6 drops to the set lower limit, the level sensor 11 sends a signal to the electric ball valve 13, the electric ball valve 13 closes, the negative pressure condensing zone 6 resumes accumulating condensate, and after the electric ball valve 13 closes, the negative pressure condensing zone 6 stops draining and continues the steam condensation process to accumulate condensate, waiting for the next drainage cycle.

[0067] S6. The electromagnetic pulse valve installed on the negative pressure vent pipe 14 near the end of the water outlet pipe 1 opens periodically at a set frequency, introducing the negative pressure from the negative pressure condensation zone 6 into the end of the water outlet pipe 1. This enhances the drainage power while preventing impurities from accumulating in the pipe through negative pressure disturbance. The pressure sensor 16 monitors the negative pressure signal in real time and feeds it back to the control mechanism to ensure stable negative pressure. The periodic opening and closing of the electromagnetic pulse valve causes the negative pressure to act intermittently on the end of the water outlet pipe 1, creating a negative pressure suction effect and enhancing the drainage power. At the same time, the negative pressure disturbance can cause fluctuations in the water flow in the pipe, preventing impurities from adhering to the inner wall of the pipe.

[0068] S7, the three-way valve 17, and the intermittent control valve 15 are synchronously activated at a set time, alternately introducing negative pressure into the beginning and end of the outlet pipe 1. Under the alternating action of negative pressure, the condensate in the pipe is driven to form a reciprocating flushing flow, thoroughly removing impurities from different sections of the pipe and further improving the anti-clogging effect. The three-way valve 17 and the intermittent control valve 15 switch synchronously, so that the negative pressure alternates at both ends of the outlet pipe 1, pushing the condensate to flow back and forth in the pipe, thoroughly flushing each section of the pipe and completely removing accumulated impurities.

[0069] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A closed-loop condensate recovery device, characterized in that, The tank (2) includes a bottom water outlet pipe (1); The tank (2) is divided into a middle steam buffer zone (4), a lower condensate collection zone (5), and an upper negative pressure condensation zone (6) by two horizontal partitions (3). The partition (3) in the middle is a sieve plate with vent holes, and the edge of the partition (3) is sealed to the inner wall of the tank (2); The upper partition (3) is a fully sealed plate. A steam guide pipe (7) is provided on the upper side of the partition (3). A one-way valve (8) that only allows steam to pass through from bottom to top is installed in the steam guide pipe (7). It also includes a steam input pipe (9), one end of which is used to connect to an external steam source, and the other end is connected to the steam buffer (4) along the radial direction of the tank (2). The negative pressure condensation zone (6) is equipped with a condensation coil (10) and a liquid level sensor (11). The condensation coil (10) is a spiral structure installed in close contact with the inner wall of the tank (2). Cooling water is introduced into the condensation coil (10) and connected to an external cooling water circulation system. The liquid level sensor (11) is a float-type liquid level sensor used to monitor the condensate level in the negative pressure condensation zone (6) in real time. The tank (2) is provided with a pressure drain pipe (12). One end of the pressure drain pipe (12) is connected to the negative pressure condensation zone (6), and the other end passes through the partition (3) in the middle and the tank (2) and is connected to the water outlet pipe (1) at the bottom. An electric ball valve (13) is provided on the drainage pipe (12), and the electric ball valve (13) is electrically connected to the liquid level sensor (11).

2. The closed-loop condensate recovery device according to claim 1, characterized in that: A negative pressure air guide pipe (14) is provided on one side of the tank (2). One end of the negative pressure air guide pipe (14) is connected to the negative pressure condensation zone (6), and the other end is connected to the end of the water outlet pipe (1). An intermittent control valve (15) and a pressure sensor (16) are provided on the negative pressure air guide pipe (14). The intermittent control valve (15) is an electromagnetic pulse valve. The intermittent control valve (15) is installed at one end of the negative pressure air guide pipe (14) near the water outlet pipe (1). The pressure sensor (16) is installed at one end of the negative pressure air duct (14) near the negative pressure condensation zone (6) to provide feedback on the negative pressure signal of the negative pressure condensation zone (6).

3. A closed-loop condensate recovery device according to claim 2, characterized in that: A three-way valve (17) is provided at the bottom end of the negative pressure air guide pipe (14), and the three-way valve (17) is a solenoid valve; The inlet of the three-way valve (17) is connected to the negative pressure air guide pipe (14), and the two outlets of the three-way valve (17) are respectively connected to the beginning and end of the water outlet pipe (1); The three-way valve (17) and the intermittent control valve (15) work together synchronously to achieve the alternating switching of negative pressure at the beginning and end of the water outlet pipe (1).

4. A closed-loop condensate recovery device according to claim 1, characterized in that: A check valve is installed on the water outlet pipe (1).

5. A closed-loop condensate recovery device according to claim 2, characterized in that: A control mechanism is provided on the outside of the tank (2), and the control mechanism is a PLC controller; The PLC controller is electrically connected to the liquid level sensor (11), the pressure sensor (16), the electric ball valve (13), and the intermittent control valve (15), respectively.

6. A closed-loop condensate recovery device according to claim 1, characterized in that: The condenser coil (10) is connected to the external cooling water circulation system by a flange connection.

7. A closed-loop condensate recovery device according to claim 1, characterized in that: A flow guide joint is provided at the connection between the flow guide pipe (12) and the water outlet pipe (1), and the flow guide joint is inclined toward the end of the water outlet pipe (1).

8. A closed-loop condensate recovery device according to claim 1, characterized in that: The drainage pipe (12) is a polyurethane heat-insulated pipe.

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