A waste heat ice melting system for a vacuum unit and its usage method

Abstract

A waste heat ice melting system for a vacuum unit and its usage method according to the present invention includes a first evaporator group, a second evaporator group, and a collection tank. The first evaporator group and the second evaporator group are arranged in parallel above the collection tank. Two steam ports are provided at the left part of the top surface of the collection tank, and are respectively connected to the first evaporator group and the second evaporator group through ice melting steam pipelines. Two wastewater ports are provided at the right part of the top surface of the collection tank, and are respectively connected to the first evaporator group and the second evaporator group through wastewater discharge pipelines. The exhaust port of the first evaporator group is connected to the vacuum unit. The present invention makes full use of the existing vacuum state in the production process and a small amount of surplus steam during the normal production of the enterprise, and combines the two perfectly, without the need to stop the machine and break the vacuum, saving resources.

Description

Technical Field

[0001] The present invention relates to the technical field of evaporator defrosting, and in particular to a waste heat defrosting system for a vacuum unit and a method for using the same. Background Art

[0002] A vacuum unit refers to a device or equipment that evacuates a container to be evacuated by mechanical, physical, and chemical methods to obtain a vacuum. The vacuum unit is widely used in industries such as metallurgy, chemical industry, food, and electronic coating. During the production process, the vacuum unit performs a vacuum pumping process on the system pipeline and the evaporator. The evaporator is the main heat exchange device in the refrigeration system, and it is a device that exchanges heat between the refrigerant and the external medium flowing through its surface. During operation, the refrigerant in the evaporator changes from a liquid state to a gaseous state to achieve a refrigeration effect.

[0003] Generally, the defrosting frequency of the evaporator in a low-temperature and high-humidity environment is relatively high. The frost layer will reduce the heat exchange efficiency of the heat exchanger, increase the energy consumption of the vacuum unit and the air supply fan. Therefore, it is of great significance to ensure the timely and effective defrosting and ice melting of the heat exchanger. In the existing ice melting process, high-temperature and high-pressure steam generated by a high-power boiler is filled into the evaporator. This process requires a large amount of energy to heat the boiler to generate high-pressure steam. Moreover, the internal temperature of the evaporator directly rises from a frozen state of -25°C to 170°C by filling high-temperature steam, which breaks the vacuum environment. After ice melting, it is necessary to re-pump the vacuum. In addition, the thermal expansion and contraction caused by the large temperature difference will have a relatively large negative impact on the welded structure, sealing structure, and cooling pipeline. In food and oil production enterprises, a large amount of steam is required for a large number of processes. If the existing process is used, a high-power boiler needs to be added, and there is a possibility of wasting some steam when ice melting is not required.

[0004] In the existing technical field, the reuse rate of the wastewater generated by the evaporator is not high, and the distilled water generated will be wasted, and the utilization of water resources cannot be well completed. Therefore, we propose a waste heat defrosting system for a vacuum unit to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above deficiencies and provide a waste heat defrosting system for a vacuum unit and a method for using the same, which improves the ice melting efficiency of the evaporator and can achieve a good ice melting effect.

[0006] The purpose of the present invention is achieved as follows:

[0007] A waste heat ice melting system for a vacuum unit, which includes a first evaporator group, a second evaporator group and a collection tank. The first evaporator group includes a first large evaporator and a first small evaporator. The second evaporator group includes a second large evaporator and a second small evaporator. The first evaporator group and the second evaporator group are arranged in parallel above the collection tank. The first large evaporator and the second large evaporator have the same structure, and the first small evaporator and the second small evaporator have the same structure;

[0008] An air inlet is provided at the upper end of the first large evaporator, and an air inlet valve is provided at the air inlet. A waste water discharge port is provided at the lower end of the first large evaporator. A chilled water inlet and outlet is provided at the bottom of the first large evaporator. Two steam inlets, one above the other, are provided on the side of the first large evaporator; An exhaust port is provided at the upper end of the first small evaporator, and an exhaust valve is provided at the exhaust port. A waste water discharge port is provided at the lower end of the first small evaporator. A chilled water inlet and outlet is provided at the bottom, and two steam inlets, one above the other, are provided on the side;

[0009] Two steam ports are provided at the left part of the top surface of the collection tank. One steam port is respectively connected to the steam inlets of the first large evaporator and the first small evaporator through an ice melting steam pipeline. The other steam port is respectively connected to the steam inlets of the second large evaporator and the second small evaporator through an ice melting steam pipeline; Two waste water ports are provided at the right part of the top surface of the collection tank. One waste water port is respectively connected to the waste water discharge ports of the first large evaporator and the first small evaporator through a waste water discharge pipeline. The other waste water port is respectively connected to the waste water discharge ports of the second large evaporator and the second small evaporator through a waste water discharge pipeline; A heating coil is arranged in the collection tank;

[0010] The exhaust ports of the first small evaporator and the second small evaporator are connected to the vacuum unit through a system pipeline. The first small evaporator is connected to the first large evaporator through a system pipeline, and the second small evaporator is connected to the second large evaporator through a system pipeline.

[0011] Further, a water replenishing port is provided on one side of the collection tank.

[0012] Further, a sewage discharge port is provided on the other side of the collection tank, and the sewage discharge port is connected to a sewage pool.

[0013] Further, a drain port is provided at the bottom surface of the collection tank.

[0014] Further, a transparent sight glass window is provided on the front surface of the collection tank.

[0015] Further, a float level gauge is also provided on the top surface of the collection tank.

[0016] Further, a temperature transmitter is also provided on the collection tank.

[0017] Further, the inlet and outlet of the chilled water of the first evaporator group and the second evaporator group are respectively connected to a chilled water tank through a chilled water pipeline, and the chilled water tank is connected to a chiller.

[0018] A method for using the waste heat ice melting system of a vacuum unit includes the following steps:

[0019] For the two evaporators of the waste heat ice melting system, one is in normal production and the other is on standby, and they are cycled and switched for use; when the evaporators are switched, valves are used for locking, and a sealed space is formed between the evaporator that needs ice melting and the collection tank, and the space is in a vacuum state of several hundred pascals;

[0020] A small amount of water is pre-added to the collection tank through the water replenishment port;

[0021] The front-stage vacuum unit performs a vacuum pumping process on the system pipeline and each evaporator;

[0022] Chilled water is introduced into each evaporator through a chilled water pipeline;

[0023] After adsorption is full, start the waste heat ice melting system, open the ice melting steam pipeline, and introduce a small amount of waste heat steam into the steam pipeline in the collection tank to heat the water. Coupled with the heating of the heating coil in the collection tank, heat it to above 50°C to generate a large amount of water vapor. This part of the water vapor enters the evaporator through the ice melting steam pipeline to melt the ice adsorbed on the evaporator system pipeline. At the same time, the condensation and adsorption effect of the ice can keep the evaporator and the collection tank in a vacuum state. Repeat this cycle until all the ice is melted.

[0024] Further, the mixture of melted ice, water, and oil enters the collection tank through the waste water discharge pipeline and is recycled through the sewage discharge port.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The present invention provides a waste heat ice melting system for a vacuum unit and its use method. Using a small amount of steam, water can be vaporized at 50°C. The generated steam flow melts the ice on the evaporator, with good ice melting effect and improved ice melting efficiency; it makes full use of the existing vacuum state in the production process and a small amount of surplus steam during the normal production of the enterprise. The two are perfectly combined, without the need to stop the machine and break the vacuum, saving resources, and meeting the production needs without additional cost; in addition, the lower temperature difference impact avoids the loss of the welding structure, sealing structure, and cooling pipeline of the evaporator, and prolongs the service life of the evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of the present invention.

[0028] Figure 2 isFigure 1 Cross-sectional view A-A

[0029] Figure 3 Side view of the present invention

[0030] Figure 4 Process flow chart of the present invention

[0031] Figure 5 Schematic diagram of the application of the present invention

[0032] Wherein:

[0033] The first evaporator group 1, the first large evaporator 1.1, the first small evaporator 1.2, the second evaporator group 2, the second large evaporator 2.1, the second small evaporator 2.2, the collection tank 3, the steam port 3.1, the waste water port 3.2, the make-up water port 3.3, the blowdown port 3.4, the drain port 3.5, the sight glass window 3.6, the heating coil 3.7, the float level gauge 3.8, the temperature transmitter 3.9, the air inlet 4, the air inlet valve 5, the exhaust port 6, the exhaust valve 7, the chilled water inlet and outlet 8, the chilled water pipeline 9, the defrosting steam pipeline 10, the waste water discharge pipeline 11, the vacuum unit 12, the chilled water tank 13, the chiller 14. Embodiment

[0034] To better understand the technical solution of the present invention, the following will be described in detail in conjunction with the relevant drawings. It should be understood that the following specific embodiments are not intended to limit the specific implementation modes of the technical solution of the present invention, and they are only the implementation modes that can be adopted by the technical solution of the present invention. It should be noted first that the description of the positional relationship of each component herein, such as component A is located above component B, is based on the relative positions of the components in the drawings and is not intended to limit the actual positional relationship of the components. Embodiment 1

[0035] See Figures 1-4 , Figure 1 A structural schematic diagram of a waste heat defrosting system of a vacuum unit is drawn. As shown in the figure, a waste heat defrosting system of a vacuum unit of the present invention includes a first evaporator group 1, a second evaporator group 2 and a collection tank 3. The first evaporator group 1 includes a first large evaporator 1.1 and a first small evaporator 1.2 which are coaxially arranged left and right and connected to each other. The second evaporator group 2 includes a second large evaporator 2.1 and a second small evaporator 2.2 which are coaxially arranged left and right and connected to each other. The first evaporator group 1 and the second evaporator group 2 are arranged in parallel above the collection tank 3 and are fixed by brackets. The first large evaporator 1.1 and the second large evaporator 2.1 have the same structure, and the first small evaporator 1.2 and the second small evaporator 2.2 have the same structure.

[0036] An air inlet 4 is provided at the upper end of the first large evaporator 1.1, and an air inlet valve 5 is provided at the air inlet 4. A waste water discharge port is provided at the lower end of the first large evaporator 1.1, a chilled water inlet and outlet 8 is provided at the bottom of the first large evaporator 1.1, and two steam inlets, one upper and one lower, are provided on the side of the first large evaporator 1.1. An exhaust port 6 is provided at the upper end of the first small evaporator 1.2, and an exhaust valve 7 is provided at the exhaust port 6. A waste water discharge port is provided at the lower end of the first small evaporator 1.2, a chilled water inlet and outlet 8 is provided at the bottom, and two steam inlets, one upper and one lower, are provided on the side.

[0037] Two steam ports 3.1 are provided at the left part of the top surface of the collection tank 3. One steam port 3.1 is respectively connected to the steam inlets of the first large evaporator 1.1 and the first small evaporator 1.2 through the ice melting steam pipeline 10, and the other steam port 3.1 is respectively connected to the steam inlets of the second large evaporator 2.1 and the second small evaporator 2.2 through the ice melting steam pipeline 10. Two waste water ports 3.2 are provided at the right part of the top surface of the collection tank 3. One waste water port 3.2 is respectively connected to the waste water discharge ports of the first large evaporator 1.1 and the first small evaporator 1.2 through the waste water discharge pipeline 11, and the other waste water port 3.2 is respectively connected to the waste water discharge ports of the second large evaporator 2.1 and the second small evaporator 2.2 through the waste water discharge pipeline 11. A water replenishing port 3.3 is provided on one side of the collection tank 3, a sewage discharge port 3.4 is provided on the other side, and the sewage discharge port 3.4 is connected to a sewage pool. A drain port 3.5 is provided at the bottom surface of the collection tank 3. A transparent sight glass window 3.6 is provided on the front surface of the collection tank 3 for observing the liquid level in the collection tank 3, and a float type liquid level gauge 3.8 is further provided on the top surface of the collection tank 3. A heating coil 3.7 is arranged in the collection tank 3, and a temperature transmitter 3.9 is further provided on the collection tank 3.

[0038] The chilled water inlets and outlets 8 of the first evaporator group 1 and the second evaporator group 2 are respectively connected to a chilled water tank 13 through a chilled water pipeline 9, and the chilled water tank 13 is connected to a chiller 14.

[0039] The exhaust ports 6 of the first small evaporator 1.2 and the second small evaporator 2.2 are connected to a vacuum unit 12 through a system pipeline. The first small evaporator 1.2 is connected to the first large evaporator 1.1 through a system pipeline, and the second small evaporator 2.2 is connected to the second large evaporator 2.1 through a system pipeline.

[0040] See Figure 5 , Figure 5 , a process flow diagram of a waste heat ice melting system of a vacuum unit is drawn. As shown in the figure, the usage method of a waste heat ice melting system of a vacuum unit of the present invention includes the following contents:

[0041] Based on the waste heat ice melting system of the above vacuum unit, there are two groups of evaporators. One group is for normal production and the other is for standby, and they are used alternately in a cycle. When the evaporators are switched, valves are used for locking to form a sealed space between the evaporator that needs ice melting and the collection tank. The pressure in this space is in the range of a few hundred pascals of vacuum. Under this vacuum state, water can boil and vaporize at forty to fifty degrees Celsius.

[0042] A small amount of water is pre-added to the collection tank through the water replenishment port.

[0043] The front-stage vacuum unit performs a vacuum pumping process on the system pipeline and each evaporator, which is used for deodorization, purification, etc. of food.

[0044] Freezing water at -25°C is introduced into each evaporator through the freezing water pipeline to adsorb and capture harmful gases such as water vapor and fatty acids in the process gas.

[0045] After being adsorbed full, start the waste heat ice melting system, open the ice melting steam pipeline, and introduce a small amount of waste heat steam into the steam pipeline in the collection tank to heat the water. Coupled with the heating of the heating coil in the collection tank, only heating to 55°C can generate a large amount of water vapor. This part of the water vapor enters the evaporator through the ice melting steam pipeline, and it can melt the ice adsorbed on the evaporator system pipeline. At the same time, the condensation and adsorption effect of the ice can keep the vacuum state in the evaporator and the collection tank continuously. Repeat this cycle until all the ice is completely melted.

[0046] The mixture of melted ice, water, and oil enters the collection tank through the waste water discharge pipeline and is recycled through the sewage discharge port.

[0047] After the ice melting, purging and other processes of the evaporator are completed, it enters the standby state.

[0048] The above is only a specific application example of the present invention and does not constitute any limitation to the protection scope of the present invention. Any technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of the protection of the present invention.

Claims

1. A waste heat ice melting system for a vacuum unit, characterized in that: It includes a first evaporator group (1), a second evaporator group (2) and a collection tank (3). The first evaporator group (1) includes a first large evaporator (1.1) and a first small evaporator (1.2) which are arranged side by side along the same horizontal axis with their central axes coinciding and connected to each other. The second evaporator group (2) includes a second large evaporator (2.1) and a second small evaporator (2.2) which are arranged side by side along the same horizontal axis with their central axes coinciding and connected to each other. The first evaporator group (1) and the second evaporator group (2) are arranged in parallel above the collection tank (3). The first large evaporator (1.1) and the second large evaporator (2.1) have the same structure, and the first small evaporator (1.2) and the second small evaporator (2.2) have the same structure; An air inlet (4) is provided at the upper end of the first large evaporator (1.1), and an air inlet valve (5) is provided at the air inlet (4). A waste water discharge port is provided at the lower end of the first large evaporator (1.1), a chilled water inlet and outlet (8) is provided at the bottom of the first large evaporator (1.1), and two steam inlets, one above the other, are provided on the side of the first large evaporator (1.1); An exhaust port (6) is provided at the upper end of the first small evaporator (1.2), and an exhaust valve (7) is provided at the exhaust port (6). A waste water discharge port is provided at the lower end of the first small evaporator (1.2), a chilled water inlet and outlet (8) is provided at the bottom, and two steam inlets, one above the other, are provided on the side; Two steam ports (3.1) are provided at the left part of the top surface of the collection tank (3). One steam port (3.1) is respectively connected to the steam inlets of the first large evaporator (1.1) and the first small evaporator (1.2) through a defrosting steam pipeline (10), and the other steam port (3.1) is respectively connected to the steam inlets of the second large evaporator (2.1) and the second small evaporator (2.2) through a defrosting steam pipeline (10); Two waste water ports (3.2) are provided at the right part of the top surface of the collection tank (3). One waste water port (3.2) is respectively connected to the waste water discharge ports of the first large evaporator (1.1) and the first small evaporator (1.2) through a waste water discharge pipeline (11), and the other waste water port (3.2) is respectively connected to the waste water discharge ports of the second large evaporator (2.1) and the second small evaporator (2.2) through a waste water discharge pipeline (11); A heating coil (3.7) is arranged in the collection tank (3); The exhaust ports (6) of the first small evaporator (1.2) and the second small evaporator (2.2) are connected to a vacuum unit (12) through a system pipeline. The first small evaporator (1.2) is connected to the first large evaporator (1.1) through a system pipeline, and the second small evaporator (2.2) is connected to the second large evaporator (2.1) through a system pipeline.

2. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: A water replenishing port (3.3) is provided on one side of the collection tank (3).

3. The waste heat ice melting system for a vacuum unit according to claim 2, characterized in that: A sewage discharge port (3.4) is provided on the other side of the collection tank (3), and the sewage discharge port (3.4) is connected to a sewage pool.

4. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: A drain port (3.5) is provided at the bottom surface of the collection tank (3).

5. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: A transparent sight glass window (3.6) is provided on the front surface of the collection tank (3).

6. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: A float level gauge (3.8) is also provided on the top surface of the collection tank (3).

7. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: A temperature transmitter (3.9) is also provided on the collection tank (3).

8. The waste heat ice melting system for a vacuum unit according to claim 1, characterized in that: The chilled water inlets and outlets (8) of the first evaporator group (1) and the second evaporator group (2) are respectively connected to a chilled water tank (13) through chilled water pipelines (9), and the chilled water tank (13) is connected to a chiller (14).

9. A method for using the waste heat ice melting system for a vacuum unit according to claim 1, characterized in that, It includes the following: Two groups of evaporators in the waste heat ice melting system, one group is for normal production and the other group is standby, and they are used alternately in a cycle; when the evaporators are switched, valves are used for locking, and a sealed space is formed between the evaporator that needs to melt ice and the collection tank, and the pressure in this space is in a vacuum state of several hundred pascals; A small amount of water is pre-added to the collection tank through the water replenishment port. The pre-stage vacuum unit conducts a vacuum pumping process on the system pipelines and each evaporator. Chilled water is introduced into each evaporator through the chilled water pipeline. After being adsorbed fully, start the waste heat ice melting system, open the ice melting steam pipeline, introduce a small amount of waste heat steam into the steam pipeline in the collection tank to heat the water, and with the heating of the heating coil in the collection tank, heat it to above 50 °C to generate a large amount of water vapor. This part of the water vapor enters the evaporator through the ice melting steam pipeline to melt the ice adsorbed on the evaporator system pipeline. At the same time, the condensation and adsorption effect of the ice can keep the evaporator and the collection tank in a vacuum state. Repeat this cycle until all the ice is completely melted.

10. The method for using the waste heat ice melting system for a vacuum unit according to claim 9, characterized in that: The mixture of melted ice, water, and oil enters the collection tank through the waste water discharge pipeline and is recycled through the sewage discharge port.

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