An apparatus for concentrating a solution using self-contained cold and hot sources

Abstract

This invention relates to the field of evaporation and concentration technology, and discloses a device for concentrating solutions using its own system's heat and cold sources. The device includes an evaporator, a condensation mechanism fixedly connected to the top of the evaporator, a raw liquid tank connected to the bottom of the condensation mechanism, a heat circulation mechanism fixedly connected to the outside of the evaporator, and a flow-dividing mechanism connected to the outside of the evaporator. The flow-dividing mechanism includes a three-way valve, with a liquid outlet end connected to the top of the three-way valve at its bottom side. A drive assembly is fixedly connected to the outside of the three-way valve, and a base is fixedly connected to the other end of the drive assembly. A support base is fixedly connected to the bottom of the three-way valve. Through a closed-loop design, hot water is transported from the heat pump unit to the heating element and then flows back to the heat pump unit from the other end of the heating element, forming a closed heat circulation loop. This loop only requires initial water replenishment and does not require a continuous external water source, avoiding the safety hazard of dry burning of the heating element and improving the stability and safety of the equipment operation.

Description

Technical Field

[0001] This invention relates to the field of evaporation and concentration technology, specifically to a device that uses its own system of cold and heat sources to concentrate a solution. Background Technology

[0002] In the operation of falling film evaporative heat pump units, the concentration management of antifreeze is crucial to ensuring the system's heat exchange efficiency and antifreeze performance. Existing antifreeze concentration processes typically employ independent evaporation systems. These systems often require an external industrial boiler or high-power electric heater as the evaporation heat source, supplemented by a cooling tower or external circulating water as the condensing medium. This high dependence on external energy sources not only results in a complex mechanical structure and large footprint for the entire unit, but also leads to heat dissipation during operation, making it impossible to effectively couple the waste heat generated within the system with the cooling energy.

[0003] Traditional equipment often employs high-temperature evaporation. In actual operation, if the liquid supply pump malfunctions or experiences flow fluctuations, the heating pipes are highly susceptible to serious mechanical accidents such as dry burning and pipe bursts under sustained high temperatures. Furthermore, existing devices largely lack precise online feedback for determining the concentration endpoint. Material switching still relies on manual valve opening or simple timed discharge. This control method struggles to respond in real-time to changes in the initial concentration of the concentrate, resulting in inconsistent finished product concentrations and a high risk of low-concentration liquid contamination. In addition, preventing the physical erosion and corrosion of metal pipes by antifreeze in a vacuum environment, and achieving automatic replenishment and resource utilization of condensate within the system, are also pressing technical bottlenecks in the design of current concentration machinery. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a device for concentrating solutions using its own system's heat and cold sources, thus solving the problem of high energy consumption caused by traditional concentration devices relying on external boilers or cooling towers.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a device for concentrating a solution using its own system's cold and heat sources, comprising an evaporator, a condensation mechanism fixedly connected to the top of the evaporator, a raw liquid tank fixedly connected to the bottom of the condensation mechanism, a heat circulation mechanism fixedly connected to the outside of the evaporator, and a diversion mechanism connected to the outside of the evaporator. The diversion mechanism includes a three-way valve, with a liquid outlet end connected to the top of the three-way valve and a drive assembly fixedly connected to the outside of the three-way valve. A base is fixedly connected to the other end of the drive assembly, and a support seat is fixedly connected to the bottom of the three-way valve.

[0006] Preferably, the drive assembly includes a rotating plate, the top of which is rotatably connected to the outside of the three-way valve, and an electric push rod is fixedly connected to the bottom of the rotating plate, with the other end of the electric push rod installed on the inside of the base.

[0007] Preferably, the heat circulation mechanism includes a heating tube installed inside the evaporator, and the heating tube circulates heat through the heating tube before flowing down from the bottom.

[0008] Preferably, the condensation mechanism includes a condenser, a delivery pipe is installed inside the condenser, one end of the delivery pipe is connected to a water pump, and a support leg is fixedly connected to the bottom of the condenser.

[0009] Preferably, the liquid outlet end of the conveying pipe enters from the side of the evaporator and extends downward to the bottom of the liquid inside the evaporator.

[0010] Preferably, a pipe is fixedly connected to the bottom of the condenser, and a water tank is installed at the bottom of the pipe for collecting condensate.

[0011] Preferably, the conveying pipe is made of stainless steel, and the evaporator is kept in a vacuum low-oxygen environment during operation.

[0012] Preferably, the bottom of the heating tube is connected to the third water pump via a pipe, and the other end of the third water pump is fixedly connected to a water outlet pipe.

[0013] Preferably, the other end of the water outlet pipe is connected to a heat pump unit, and an inlet pipe is installed on the outside of the heat pump unit. The other end of the inlet pipe is fixedly connected to a water pump.

[0014] Preferably, one end of the water pump is connected to the raw liquid tank via a pipe, and the other end is connected to the evaporator, so as to transport the raw liquid to the evaporator while using the residual heat of the steam in the evaporator to preheat the raw liquid.

[0015] This invention provides a device for concentrating solutions using its own system of cold and heat sources. It has the following beneficial effects: 1. The heating circulation system of this invention adopts a closed-loop design. Hot water is transported from the heat pump unit to the heating element and then flows back to the heat pump unit from the other end of the heating element, forming a closed heat circulation loop. This loop only requires initial water replenishment and does not require a continuous external water source, avoiding safety hazards such as dry burning and pipe bursting of the heating element, thus improving the stability and safety of equipment operation. At the same time, this closed-loop design, combined with a vacuum negative pressure evaporation environment, allows the low-temperature hot water of 50 to 60 degrees Celsius provided by the heat pump unit to meet the heating requirements, reducing system energy consumption and achieving a dual improvement in safety and energy efficiency.

[0016] 2. This invention recovers the waste heat released by the condensation of water vapor through a condenser, which is used to preheat the liquid to be concentrated, thus realizing the secondary utilization of waste heat and effectively improving the system energy efficiency. At the same time, the condensate generated can be used for equipment flushing, industrial water, or to supplement the water loss of the heating circulation system, realizing the recycling of water resources and reducing operating costs.

[0017] 3. This invention uses an electric push rod of the diversion mechanism to drive a three-way pipe, which can accurately switch the pipeline according to the concentration setting value, ensuring that unqualified liquid is recirculated and evaporated, and qualified concentrate is directly output, thus ensuring the consistency and stability of product concentration. At the same time, the stainless steel delivery pipe in the condenser enters the evaporator from the side and extends to the bottom of the liquid, avoiding direct contact and mixing of water vapor with the delivery pipe opening, preventing the solution from contaminating the liquid to be concentrated, and ensuring product purity. Attached Figure Description

[0018] Figure 1 This is a perspective view of the present invention; Figure 2 This is a cross-sectional view of the condenser of the present invention; Figure 3 This is a schematic diagram of the thermal circulation mechanism of the present invention; Figure 4 This is a schematic diagram of the diversion mechanism of the present invention; Figure 5 This is a cross-sectional view of the evaporator of the present invention.

[0019] The components include: 1. Evaporator; 2. Condensation mechanism; 21. Condenser; 22. Delivery pipe; 23. Support leg; 24. Water pump one; 25. Water tank; 26. Pipeline; 3. Heat circulation mechanism; 31. Heat pump unit; 32. Inlet pipe; 33. Outlet pipe; 34. Water pump two; 35. Water pump three; 36. Heating tube; 4. Diversion mechanism; 41. Base; 42. Drive assembly; 421. Electric push rod; 422. Rotating plate; 43. Support seat; 44. Three-way valve; 5. Raw material tank. Detailed Implementation

[0020] The technical solutions in 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.

[0021] Please see the appendix Figure 1 -Appendix Figure 4This invention provides a device for concentrating a solution using its own system's heat and cold sources. The device includes an evaporator 1, which serves as the core container for the entire concentration process, providing a vacuum negative pressure environment to ensure efficient evaporation of the liquid at a relatively low boiling point. A condensing mechanism 2 is fixedly connected to the top of the evaporator 1. This mechanism captures and recovers the water vapor generated during evaporation, reducing its temperature through heat exchange and causing it to condense and liquefy. A raw liquid tank 5 is connected to the bottom of the condensing mechanism 2. This tank stores the liquid to be concentrated and preheats it using the heat from condensation before it enters subsequent processes. A heat circulation mechanism 3 is fixedly connected to the outside of the evaporator 1, providing continuous and stable medium-to-low temperature heat energy to the interior of the evaporator 1, ensuring the concentration process operates within a safe temperature range.

[0022] Specifically, with evaporator 1 as the core, the boiling point of the solution is lowered under negative pressure to achieve low-temperature and high-efficiency concentration. The raw liquid to be concentrated is first stored in raw liquid tank 5, and the raw liquid is preheated by the heat released during the condensation of water vapor by condensation mechanism 2, so as to realize the recovery and utilization of condensation waste heat and improve the system energy efficiency.

[0023] The preheated raw liquid enters the evaporator 1. The heat circulation mechanism 3 continuously provides a stable medium-low temperature heat energy to the evaporator 1, driving the liquid to evaporate rapidly under negative pressure. The generated water vapor rises to the condensation mechanism 2 at the top. The condensation mechanism 2 cools and condenses the water vapor into liquid water through heat exchange and then recovers it.

[0024] Please see the appendix Figure 1 Appendix Figure 2 and attached Figure 5An external diversion mechanism 4 is connected to the outside of the evaporator 1. The diversion mechanism 4 guides the fluid path based on real-time concentration monitoring, ensuring the stability of the output product's quality. The diversion mechanism 4 includes a three-way valve 44, which serves as the core actuator for flow path switching, flexibly switching between the return pipeline and the finished product output pipeline. The top of the three-way valve 44 is connected to a liquid outlet on its side bottom. This connection layout facilitates the smooth entry of concentrated liquid from the bottom of the evaporator 1 into the switching system, reducing fluid transmission resistance. A drive assembly 42 is fixedly connected to the outside of the three-way valve 44, providing mechanical power for the switching action of the three-way valve 44 and achieving automated control of the diversion process. A base 41 is fixedly connected to the other end of the drive assembly 42, providing a stable support platform for the entire drive structure and absorbing vibrations generated by mechanical action. A support seat 43 is fixedly connected to the bottom of the three-way valve 44, bearing the weight of the three-way valve 44 and its associated pipelines, ensuring the stability of the mechanical structure during frequent flow direction switching. The drive assembly 42 includes a rotating plate 422, which acts as a power transmission component, converting thrust into the rotational torque of the valve core, thus improving the accuracy of the switching action. The top of the rotating plate 422 is rotatably connected to the outside of the three-way valve 44. This rotating fit structure reduces friction, ensuring that the three-way valve 44 responds promptly after a diversion command is issued. An electric push rod 421 is fixedly connected to the bottom of the rotating plate 422. The electric push rod 421 has precise displacement output capability, pulling the rotating plate 422 through its extension and retraction to complete the flow path switching control. The other end of the electric push rod 421 is installed inside the base 41. This reasonable installation position balances the mechanical force support point, enhancing the stability of the push rod's operation.

[0025] Specifically, a diversion mechanism 4 consisting of a base 41, a drive assembly 42, a support 43, and a three-way valve 44 is installed on the outside of the evaporator 1. The electric push rod 421 extends and retracts to drive the rotating plate 422 to rotate, thereby driving the valve core of the three-way valve 44 to move. This automatically switches the fluid path so that the concentrate is reasonably guided between the return pipeline and the finished product output pipeline. Automatic diversion control is achieved under stable support and low friction response conditions to ensure stable finished product concentration.

[0026] Please see the appendix Figure 1 Appendix Figure 2 and attached Figure 3 The heat circulation mechanism 3 includes a heating tube 36, which transfers the heat energy of the hot water to the liquid to be concentrated inside the tank, serving as a direct heat source for water vaporization. The heating tube 36 is installed inside the evaporator 1 and is immersed in the liquid for indirect heat exchange, allowing water to continuously vaporize into water vapor under vacuum. After circulating heat exchange with hot water inside the heating tube 36, the water flows down from the bottom. The hot water releases heat within the tube and then flows back to the heating source to reheat, forming a closed-loop heat transfer medium circuit.

[0027] Specifically, the heating tube 36 of the heat circulation mechanism 3 is installed inside the evaporator 1 and immersed in the liquid to be concentrated. The heat energy is transferred through the hot water circulating inside the tube, realizing indirect heat exchange and vaporization of the liquid to be concentrated. After the hot water releases heat, it flows back to the heating source to reheat, forming a closed heat system.

[0028] Please see the appendix Figure 1 -Appendix Figure 4 The condensing mechanism 2 includes a condenser 21, which provides a sealed gas-liquid exchange space and utilizes the phase change principle to achieve efficient water recovery. A delivery pipe 22 is installed inside the condenser 21. The low-temperature liquid flowing inside the delivery pipe 22 condenses the water vapor outside the pipe, while the liquid itself absorbs latent heat to preheat, improving energy efficiency. One end of the delivery pipe 22 is connected to a water pump 24, which provides stable circulation power, ensuring that the raw liquid passes through the condenser 21 at a constant flow rate. A support leg 23 is fixedly connected to the bottom of the condenser 21, which stably supports the condenser 21 at a predetermined height, ensuring the rationality of the pipeline layout. The liquid outlet of the delivery pipe 22 enters from the side of the evaporator 1. This path design shortens the transmission path of the preheated liquid into the evaporator 1, reducing heat loss. It extends downwards to the bottom of the liquid inside the evaporator 1, with the pipe opening located below the liquid surface to avoid contact and mixing between the feed and the steam above, while also reducing physical erosion and wear on the pipeline. The conveying pipe 22 is made of stainless steel, which effectively resists the corrosion of liquids and the vacuum low-oxygen environment, extending the service life of the equipment. The evaporator 1 maintains a vacuum low-oxygen environment during operation. This specific physical environment lowers the boiling point of the solvent and effectively prevents material oxidation loss. A pipe 26 is fixedly connected to the bottom of the condenser 21, guiding the condensed liquid water to a collection container to ensure pressure balance inside the condenser 21. A water tank 25 is installed at the bottom of the pipe 26 to collect the condensate. The collected water can be used to replenish the water loss in the heating circulation system, realizing resource utilization.

[0029] Specifically, the condensing mechanism 2 is centered around the condenser 21, with support legs 23 providing stable support at a predetermined height, ensuring reasonable pipeline layout and overall structural stability. During operation, the evaporator 1 maintains a vacuum low-oxygen environment to lower the solvent boiling point and prevent oxidation loss. The water vapor generated during vaporization rises to the sealed gas-liquid exchange space within the condenser 21. Simultaneously, the water pump 24 provides stable circulation power, driving the concentrate to flow into the stainless steel delivery pipe 22 at a constant flow rate. The low-temperature concentrate flows along the delivery pipe 22 inside the condenser 21, absorbing the latent heat of the water vapor outside the pipe during the flow, thus preheating itself. To improve system energy efficiency, water vapor is condensed into liquid water under the principle of phase change. The preheated raw liquid continues to flow along the conveying pipe 22, passes through the side of the evaporator 1 and extends downward to the bottom of the liquid in the tank, avoiding contact and mixing between the feed and the steam above, and reducing the scouring and wear of the pipeline. The pipe 26 at the bottom of the condenser 21 guides the condensed liquid water to the water tank 25 below for collection, which not only ensures the internal pressure balance of the condenser 21, but also allows the collected water to be used to supplement the water loss of the heating circulation system, realizing resource recycling. All structures work together to complete the continuous process of steam condensation, raw liquid preheating and water resource recovery.

[0030] Please see the appendix Figure 1 Appendix Figure 2 and attached Figure 3 The bottom of heating element 36 is connected to water pump 35 via a pipe. Water pump 35 is responsible for drawing warm water from heating element 36 after releasing heat, maintaining the circulation in the pipeline. A water outlet pipe 33 is fixedly connected to the other end of water pump 35, serving as a return water channel to guide the warm water smoothly towards the heat compensation end. The other end of water outlet pipe 33 is connected to heat pump unit 31, which provides hot water at 50-60 degrees Celsius, fundamentally avoiding the risk of dry burning and pipe bursting of heating element 36 through gentle heating. A water inlet pipe 32 is installed on the outside of heat pump unit 31, which sends the reheated hot water to the heating section, ensuring a continuous heat source supply. The other end of water inlet pipe 32 is fixedly connected to water pump 34 via a pipe, which provides delivery pressure to the heating circuit, ensuring smooth flow of hot water inside heating element 36. The other end of the water pump 24 is connected to the raw liquid tank 5 via a pipe. This connection method creates a sealed transport channel for the raw liquid from the storage tank to the evaporation core. The other end is connected to the evaporation tank 1. The closed transport structure can effectively utilize the waste heat released by the condensation of water vapor to preheat the raw liquid, realize the secondary utilization of waste heat and improve the overall system energy efficiency.

[0031] Specifically, the heating element 36 and its associated structure use the heat pump unit 31 as the core for heat compensation, and together with water pumps 24 and 35 and various pipelines, form a complete heat circulation loop. Simultaneously, water pump 24 connects the raw liquid tank 5 and the evaporator 1 to form a raw liquid preheating and delivery loop. These two loops work together to ensure stable system operation. During operation, the hot water in the heating element 36 releases heat to provide a heat source for the vaporization of the liquid in the evaporator 1, and then cools to warm water. At this time, water pump 35 starts, generating suction power to extract the warm water from the bottom of the heating element 36, maintaining the circulating flow of fluid within the pipeline. Driven by water pump 35, the warm water flows smoothly along the outlet pipe 33 to the heat pump unit 31, where it is heated to 50-60 degrees Celsius to form hot water. This temperature setting avoids the heating element... 36. Risk of dry burning and pipe bursting; After heating, the hot water is transported to water pump 2 34 through water inlet pipe 32. Water pump 2 34 provides a stable delivery pressure, pushing the hot water along the pipeline into the interior of heating pipe 36, realizing the circulation and replenishment of hot water, and ensuring that heating pipe 36 continuously provides a stable heat source for evaporator 1; At the same time, water pump 1 24 is connected to the raw liquid tank 5 and evaporator 1 at both ends, respectively, to form a sealed raw liquid delivery channel. Driven by water pump 1 24, the raw liquid flows out from the raw liquid tank 5, flows through condenser 21 to absorb the waste heat released by water vapor condensation and complete the preheating, and then is transported to evaporator 1. The closed delivery structure realizes the secondary utilization of waste heat, effectively improving the overall system energy efficiency. All structures cooperate and move in an orderly manner to complete the continuous process of heat circulation supply and raw liquid preheating delivery.

[0032] Working principle: When the heat circulation mechanism 3 is working, a vacuum negative pressure environment is first formed in the evaporator tank 1. The liquid to be concentrated is transported to the evaporator tank 1 by water pump 24, so that the liquid to be concentrated can evaporate at a relatively low boiling point. Hot water of 50 to 60 degrees Celsius provided by the heat pump unit 31 is used as the heating medium. The hot water is transported from the outlet pipe 33 to the heating tube 36 by water pump 34. It circulates in a closed loop in the heating tube 36, and indirectly exchanges heat with the liquid to be concentrated in the evaporator tank 1, so that the water in the liquid continuously vaporizes to form water vapor. After the hot water releases heat, the temperature drops, and it flows back to the heat pump unit 31 through the inlet pipe 32 via water pump 35 for reheating, forming a closed loop heating circuit. Only the initial water replenishment is required, and no continuous external water source is needed, avoiding safety hazards such as dry burning and tube bursting of the heating tube 36.

[0033] The water vapor generated by evaporation enters the condenser 21 in the condensation mechanism 2 through the pipeline. The condenser 21 has a delivery pipe 22 for the flow of cryogenic antifreeze. The other end of the delivery pipe 22 enters the evaporator 1 from the side and extends to the bottom of the liquid inside the tank, preventing the evaporated water vapor from directly contacting and mixing with the opening of the delivery pipe 22. The delivery pipe 22 is made of stainless steel, which, combined with the vacuum low-oxygen environment and corrosion resistance, effectively reduces corrosion and wear. The cryogenic antifreeze cools the water vapor, causing it to condense into water droplets on the outer wall of the coil and fall onto the inner wall of the condenser 21. The condensate is then transported to the water tank 25 through the pipe 26 and can be used for equipment flushing, industrial water, or to replenish water losses in the heating circulation system. Simultaneously, the waste heat released by the condensation of water vapor is recovered and can be used to preheat the liquid to be concentrated, achieving secondary utilization of waste heat and improving system energy efficiency.

[0034] The diversion mechanism 4 operates during the concentration process by using an electric push rod 421 in the drive assembly 42 to push a rotating plate 422, which in turn drives a three-way valve 44 to perform diversion control: when the concentration does not meet the standard, the valve switches the pipeline and sends the unqualified liquid back into the original liquid tank 5 to continue circulating and evaporating; when the concentration reaches the set value, the valve switches to the finished product output pipeline, and the qualified concentrated liquid is directly discharged for collection or quantitatively packaged into barrels.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for concentrating a solution using the cold and hot sources of the own system, comprising an evaporation tank (1), characterized in that, The top of the evaporation tank (1) is fixedly connected with a condensing mechanism (2), the bottom of the condensing mechanism (2) is connected with an original liquid tank (5), the outer side of the evaporation tank (1) is fixedly connected with a heat circulation mechanism (3), and the outer side of the evaporation tank (1) is connected with a shunt mechanism (4). The shunt mechanism (4) comprises a three-way valve (44), the top of the three-way valve (44) is connected with a side bottom liquid outlet, the outer side of the three-way valve (44) is fixedly connected with a driving assembly (42), the other end of the driving assembly (42) is fixedly connected with a base (41), and the bottom of the three-way valve (44) is fixedly connected with a supporting seat (43).

2. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 1, wherein The driving assembly (42) comprises a rotating plate (422), the top of the rotating plate (422) is rotatably connected to the outer side of the three-way valve (44), the bottom of the rotating plate (422) is fixedly connected with an electric push rod (421), and the other end of the electric push rod (421) is mounted on the inner side of the base (41).

3. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 1, wherein The heat circulation mechanism (3) comprises a heating pipe (36), the heating pipe (36) is mounted in the evaporation tank (1), and the heating pipe (36) internally completes circulation heat exchange by hot water and then flows down from the bottom.

4. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 3, wherein The condensing mechanism (2) comprises a condenser (21), the condenser (21) is internally mounted with a conveying pipe (22), one end of the conveying pipe (22) is connected with a water pump I (24), and the bottom of the condenser (21) is fixedly connected with a supporting leg (23).

5. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 4, wherein The liquid outlet of the conveying pipe (22) penetrates from the side of the evaporation tank (1) and extends downward to the bottom of the liquid in the evaporation tank (1).

6. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 4, wherein The bottom of the condenser (21) is fixedly connected with a pipeline (26), and the bottom of the pipeline (26) is mounted with a water tank (25) for collecting condensed water.

7. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 4, wherein The conveying pipe (22) is made of stainless steel, and the evaporation tank (1) maintains a vacuum low-oxygen environment in the working state.

8. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 3, wherein The bottom of the heating pipe (36) is connected with a water pump III (35) through a pipe, and the other end of the water pump III (35) is fixedly connected with a water outlet pipe (33).

9. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 8, wherein, The other end of the water outlet pipe (33) is connected with a heat pump unit (31), the outer side of the heat pump unit (31) is mounted with a water inlet pipe (32), and the other end of the water inlet pipe (32) is fixedly connected with a water pump II (34) through a pipe.

10. The apparatus for concentrating a solution using a cold heat source of the body system according to claim 4, wherein The other end of the water pump I (24) is connected with the original liquid tank (5) through a pipe, the other end is communicated with the evaporation tank (1), and the original liquid is conveyed to the evaporation tank (1) while the original liquid is preheated by the steam waste heat in the evaporation tank (1).

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