Efficient hot air circulating system device

Abstract

The invention discloses an efficient hot air circulating system device which comprises a heating main pipeline, a heating pipe, a hot air circulating inlet, a hot air circulating outlet, a circulating fan and an air duct inlet and further comprises a preheating air duct pipe used for preheating air entering the heating main pipeline and a heat preservation layer used for heat preservation. The preheating air duct pipe is attached to the outer wall of the heating main pipeline in a spiral winding mode, the air duct inlet is formed in an inlet of the preheating air duct pipe, an outlet of the preheating air duct pipe is communicated with the heating main pipeline, and the heat preservation layer is arranged on the outer side of the preheating air duct pipe in a wrapping mode. Cold air is fully preheated for the first time through the preheating air duct pipe and then enters the heating main pipeline to be heated for the second time, the synergistic effect of the heat preservation layer is combined, heat loss is reduced, dissipated heat is fully utilized for preheating, meanwhile, the needed temperature can be achieved without additional air volume compensation, and the comprehensive energy efficiency of the system is improved; and the preheating air duct pipe is tightly attached to the heating main pipeline, so that the structure is compact.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial heating equipment and can be applied to scenarios such as drying and heat treatment. Specifically, it is an efficient hot air circulation system device. Background Art

[0002] The purpose of the hot air circulation system in industrial heating equipment is to keep the temperature in the heating equipment stable and uniform, ensuring that the processed components in the heating equipment can be heat-treated within a small temperature difference range.

[0003] The traditional hot air circulation system has the following problems: (1) The efficiency of the air-heat coupling is low, the contact time between the incoming air and the heating part of the heating pipe is short, and the preheating is insufficient, resulting in unstable temperature in the heating pipe; (2) The effective heating power needs to meet the heat required for the air temperature rise. When the heat loss increases, the effective heating power decreases. To achieve the same temperature rise, it is necessary to increase the air volume to compensate, resulting in an increase in energy consumption. Contents of the Invention

[0004] In view of this, the purpose of the present invention is to provide an efficient hot air circulation system device.

[0005] To solve the above technical problems, the technical solution of the present invention is:

[0006] An efficient hot air circulation system device includes a main heating pipe, a heating tube arranged on the inner wall of the main heating pipe, a hot air circulation inlet and a hot air circulation outlet arranged before and after the main heating pipe, a circulation fan communicated with the main heating pipe, and an air duct inlet communicated with the main heating pipe. It also includes a preheating air duct pipe for preheating the air entering the main heating pipe and a heat insulation layer for heat preservation. The preheating air duct pipe is arranged between the air duct inlet and the main heating pipe. The preheating air duct pipe is spirally wound around the outer wall of the main heating pipe. The air duct inlet is arranged at the inlet of the preheating air duct pipe. The outlet of the preheating air duct pipe is communicated with the main heating pipe. The heat insulation layer is coated on the outside of the preheating air duct pipe.

[0007] Preferably, the outlet of the preheating air duct pipe communicated with the main heating pipe is arranged close to the hot air circulation inlet, and the preheated air quickly enters the main heating pipe for secondary heating.

[0008] Preferably, the preheating air duct pipe is spirally wound around the outer wall of the main heating pipe for two or more turns.

[0009] Preferably, the cross-section of the preheating air duct pipe is formed into a rectangle to increase its contact area with the outer wall of the main heating pipe.

[0010] Preferably, the air duct inlet is laterally arranged perpendicular to the outer wall of the main heating pipeline.

[0011] Preferably, both the main heating pipeline and the preheating air duct are made of stainless steel.

[0012] Preferably, the heat insulation layer is an asbestos heat insulation layer formed by block molding, and a high-temperature resistant adhesive is coated between the block joints of the asbestos heat insulation layer.

[0013] The technical effects of the present invention are mainly reflected in the following aspects: Before the cold air enters the main heating pipeline from the air duct inlet, it is fully preheated once through the preheating air duct spirally wound around the outer wall of the main heating pipeline, and then enters the main heating pipeline for secondary heating. Combining with the synergistic effect of the heat insulation layer to inhibit the heat dissipation from the outer wall of the main heating pipeline, not only reduces the heat loss of the outer wall of the main heating pipeline, but also makes full use of the heat dissipated from the outer wall of the main heating pipeline for preheating, improving the comprehensive energy efficiency of the system; reducing heat loss, increasing the effective heating power, and achieving the required temperature without additional compensation for air volume, which can also reduce energy consumption; the preheating air duct is closely attached to the main heating pipeline, making the structure compact and without increasing the volume of the hot air circulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the overall structure of the present invention

[0015] Figure 2 is a front schematic diagram of the overall structure of the present invention;

[0016] Figure 3 is a side schematic diagram of the overall structure of the present invention;

[0017] Figure 4 is a partial schematic diagram of the present invention.

[0018] 1 - Main heating pipeline; 2 - Hot air circulation inlet; 3 - Hot air circulation outlet; 4 - Air duct inlet; 5 - Preheating air duct; 51 - Inlet of the preheating air duct; 52 - Outlet of the preheating air duct; 6 - Heat insulation layer. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following further details the specific embodiments of the present invention in conjunction with the drawings, so that the technical solutions of the present invention are easier to understand and master.

[0020] Example 1:

[0021] According to Figures 1-4As shown, an efficient hot air circulation system device includes a main heating duct 1, heating tubes arranged on the inner wall of the main heating duct 1, a hot air circulation inlet 2 and a hot air circulation outlet 3 arranged before and after the main heating duct 1, a circulation fan communicated with the main heating duct 1, and a duct inlet 4 communicated with the main heating duct 1. The main heating duct 1 can be made of stainless steel material. In the traditional hot air circulation system, cold air is heated only after entering the main heating duct 1 from the duct inlet 4, which not only consumes the heat in the main heating duct 1, but also the heat dissipated from the outer wall of the main heating duct 1 is not effectively utilized, resulting in low energy efficiency.

[0022] In this application, the hot air circulation system further includes a preheating duct 5 for preheating the air entering the main heating duct 1 and a heat insulation layer 6 for heat preservation. The preheating duct 5 can be made of the same stainless steel material as the heating duct. The preheating duct 5 is arranged between the duct inlet 4 and the main heating duct 1. The preheating duct 5 is spirally wound around the outer wall of the main heating duct 1. The preheating duct 5 can be wound around the outer wall of the main heating duct 1 by a numerical control winding machine. The duct inlet 4 is arranged at the inlet 51 of the preheating duct. The outlet 52 of the preheating duct is communicated with the main heating duct 1. Cold air enters the preheating duct 5 from the duct inlet 4 and is fully preheated once by the heat absorbed from the outer wall of the main heating duct 1 through the preheating duct 5, and then enters the main heating duct 1 from the outlet 52 of the preheating duct for secondary heating, without consuming the heat in the main heating duct 1, greatly reducing heat loss. At the same time, the heat insulation layer 6 is coated on the outside of the preheating duct 5. Under the synergistic effect of the preheating duct 5 and the heat insulation layer 6, the heat dissipation from the outer wall of the main heating duct 1 is inhibited, and the comprehensive energy consumption of the system is improved.

[0023] In order to further reduce heat loss and improve the temperature stability of hot air circulation, the outlet of the preheating duct 5 communicated with the main heating duct 1 is arranged close to the hot air circulation inlet 2. The air preheated by the preheating duct 5 quickly enters the main heating duct 1 for secondary heating. The air entering the hot air circulation after secondary heating can reduce the influence of external air entering the hot air circulation system on the temperature.

[0024] Specifically, in order to enable the cold air to be fully preheated in the preheating duct 5, the preheating duct 5 can also be spirally wound around the outer wall of the main heating duct 1 for two or more turns, so that the cold air has enough time for heat exchange in the preheating duct 5.

[0025] The cross-section of the preheating air duct pipe 5 is formed into a rectangle. Compared with the circular cross-section, the rectangular cross-section of the preheating air duct pipe 5 can increase its contact area with the outer wall of the main heating pipe 1, improve the heat exchange efficiency, and make greater use of the heat dissipated from the outer wall of the main heating pipe 1.

[0026] In order to increase the wind speed entering the preheating air duct pipe 5 and improve the efficiency of the circulation fan, the air duct inlet 4 is laterally arranged perpendicular to the outer wall of the main heating pipe 1.

[0027] In this application, the heat insulation layer 6 is an asbestos heat insulation layer 6 formed by block molding, which is convenient for the production and installation of the heat insulation layer 6. A high-temperature resistant adhesive is coated between the block joints of the asbestos heat insulation layer 6.

[0028] In actual use, it is preset that the main heating pipe 1 made of stainless steel has an outer diameter of 90 mm and a wall thickness of 3 mm, the voltage of the heating tube is 480 V, and the length of the heating section is 246 mm;

[0029] The cross-section of the preheating air duct pipe 5 is a stainless steel square pipe with a size of 15 mm × 15 mm and a wall thickness of 1 mm. It is spirally wound around the outer wall of the main heating pipe 1 for 263 mm, with the inlet arranged laterally and the outlet communicating with the main heating pipe 1;

[0030] The heat insulation layer 6 is made of 38 mm thick asbestos material and is coated outside the preheating air duct pipe 5, and its thermal conductivity .

[0031] When there is no preheating air duct pipe 5 on the main heating pipe 1, assuming the temperature difference reaches = 200 °C, the heat loss of the main heating pipe 1 :

[0032]

[0033] When there is a preheating air duct pipe 5 on the main heating pipe 1, assuming the temperature difference reaches = 50 °C, the heat loss of the main heating pipe 1 :

[0034]

[0035] Air volume requirement without the preheating air duct pipe 5 (air temperature rise = 200 °C):

[0036] Effective heating power ,

[0037] ;

[0038]

[0039] When there is the preheating air duct pipe 5, the air volume demand (air temperature rise = 50 °C):

[0040] Effective heating power ,

[0041] ;

[0042]

[0043] Fan power consumption (rectangular preheating air duct pipe resistance 0.48 Pa, efficiency 60%):

[0044]

[0045] , air volume is positively correlated with the effective heating power and negatively correlated with the air temperature rise .

[0046] When there is no preheating air duct pipe 5, in order to transfer the same amount of heat , the generated air volume is insufficient and additional air volume needs to be supplemented. Compared with the case of having the preheating air duct pipe 5, the energy consumption increases.

[0047] Among them, the above symbols represent:

[0048] represents the heat loss power, with the unit of watt ( ), which represents the heat dissipated into the environment during the operation of the system;

[0049]

[0050] is the pipe length, which directly determines the total surface area of heat loss.

[0051] is the overall heat transfer coefficient, with the unit , which is a heat transfer efficiency parameter integrating conduction, convection and radiation, .

[0052] is the material thermal conductivity.

[0053] is the temperature difference, with the unit of degree Celsius (°C), which is the driving force for heat transfer and directly affects the heat loss and energy consumption calculation of thermal efficiency,

[0054] Calculation of heat output: , For air quality, is the specific heat capacity;

[0055] is the air weight of the circulation heater, equal to the air volume flow rate ( ) × air density ( );

[0056] Radiator efficiency evaluation: The greater the temperature difference, the higher the heat output efficiency.

[0057] By comparing the heat losses in two cases, it is obvious that the addition of the preheating air duct and the insulation layer significantly reduces the heat energy dissipation;

[0058] Indicates no preheating pipeline: ;

[0059] Indicates there is a preheating pipeline. When calculating the thermal resistance of the insulation material, the thickness of the insulation layer , the ratio of the inner and outer diameters and other parameters need to be introduced.

[0060] Indicates the effective heating power ( ), the actual available power after subtracting the heat loss from the total power,

[0061] .

[0062] Indicates the air volume flow rate, unit ( or ), which is the volume of gas transported per unit time;

[0063] Air volume flow rate requirement: ;

[0064] is the air density, unit ( ), which affects the heat capacity and fan power consumption in the calculation of the air volume flow rate;

[0065] is the specific heat capacity, unit ( ), the heat required for a unit mass of the substance to increase by 1°C. The common value for air is 1005 .

[0066] Fan power consumption: ;

[0067] is the air duct resistance, unit (Pa), which is composed of frictional resistance and local resistance;

[0068] is the fan efficiency, divided into fan efficiency ( ), and mechanical transmission efficiency ( ),

[0069] .

[0070] Table 1 Optimization effect

[0071]

[0072] Table 1 shows that this application not only reduces the heat loss on the outer wall of the main heating pipeline, but also makes full use of the heat dissipated from the outer wall of the main heating pipeline for preheating, improving the comprehensive energy efficiency of the system; the heat loss is reduced, the effective heating power is increased, and the required temperature can be reached without additional compensation for the air volume, which can also reduce the energy consumption.

Claims

1. An efficient hot air circulation system device, comprising a main heating pipeline, a heating tube arranged on the inner wall of the main heating pipeline, a hot air circulation inlet and a hot air circulation outlet arranged before and after the main heating pipeline, a circulation fan communicated with the main heating pipeline, and an air duct inlet communicated with the main heating pipeline, characterized in that: It further includes a preheating air duct for preheating the air entering the main heating pipeline and a heat insulation layer for heat preservation. The preheating air duct is arranged between the air duct inlet and the main heating pipeline. The preheating air duct is spirally wound and attached to the outer wall of the main heating pipeline. The air duct inlet is arranged at the inlet of the preheating air duct. The outlet of the preheating air duct is communicated with the main heating pipeline. The heat insulation layer is coated on the outside of the preheating air duct.

2. An efficient hot air circulation system device according to claim 1, characterized in that: The outlet of the preheating air duct communicated with the main heating pipeline is arranged near the hot air circulation inlet, and the preheated air quickly enters the main heating pipeline for secondary heating.

3. An efficient hot air circulation system device according to claim 1, characterized in that: The preheating air duct is spirally wound around the outer wall of the main heating pipeline for two or more turns.

4. An efficient hot air circulation system device according to claim 1, characterized in that: The cross section of the preheating air duct is formed into a rectangle to increase its contact area with the outer wall of the main heating pipeline.

5. An efficient hot air circulation system device according to claim 1, characterized in that: The air duct inlet is arranged laterally perpendicular to the outer wall of the main heating pipeline.

6. An efficient hot air circulation system device according to any one of claims 1-5, characterized in that: Both the main heating pipeline and the preheating air duct are made of stainless steel materials.

7. An efficient hot air circulation system device according to claim 1, characterized in that: The heat insulation layer is an asbestos heat insulation layer formed by block molding, and a high-temperature resistant adhesive is coated between the block joints of the asbestos heat insulation layer.

Images