Drying device for high-speed high-gram-weight wet-process non-woven fabric production line

Abstract

The utility model discloses a drying device for a high-speed high-gram-weight wet-process non-woven fabric production line, and belongs to the field of non-woven fabric generation equipment. According to the utility model, the plurality of drying cylinders and the suction type drying equipment are adopted to form one-stage combined drying equipment, and then the multi-stage combined drying equipment is connected in series, so that the overall drying efficiency is improved in a mode of alternately performing temperature rise heating and suction moisture removal. The wet fiber layer is heated through the drying cylinder, after water molecules are activated and become water vapor, the water vapor is pumped out through the suction type drying equipment, and then the wet fiber layer is conveyed into the next-stage combined drying equipment to continue to be dried in the mode of heating through the drying cylinder and sucking through the suction type drying equipment. In the process of continuously, repeatedly and gradually drying, the temperature of the drying cylinder and the suction air quantity in each stage can be controlled, water molecules generated by vaporization in a wet fiber layer can be timely pumped out, and the drying efficiency is improved, so that the productivity of wet-process non-woven fabrics is increased, and the energy consumption is reduced.

Description

Technical Field

[0001] The utility model belongs to the field of non-woven fabric production equipment, and in particular relates to a drying device used for a high-speed and high-weight wet-laid non-woven fabric production line. Background Art

[0002] The wet non-woven production line is to disperse various fibers with water and evenly place them in various forming devices. After dehydration, the fibers are deposited on the forming net to form a wet fiber layer. The wet fiber net is entangled with high-pressure water needles or with adhesive fibers and surface coating adhesive materials. After drying, a non-woven fabric with a certain strength is formed. In the production process of wet non-woven fabrics, the quality of drying determines the performance and cost of non-woven fabrics, and is an important link in the production process of wet non-woven fabrics. At present, most of the drying of wet non-woven fabrics adopts the following drying methods:

[0003] 1. Use a drying drum: Steam and heat-conducting oil are introduced into the drying drum to heat the surface of the drying drum. The wet fiber layer contacts the surface of the drying drum and heats the fiber layer through heat conduction. According to the weight and speed of the fiber layer, the surface temperature of the drying drum is adjusted or the number of drying drums is increased to remove moisture from the wet fiber layer to make non-woven fabrics.

[0004] 2. Use an oven: introduce the wet fiber layer onto the conveyor net, use the dry hot air blown out by the heat exchanger to heat the surface of the wet fiber layer, heat and volatilize the moisture in the wet fiber layer through heat exchange, and then discharge the hot air containing water. The wet fiber layer is attached to the conveyor net and is heated and exhausted by hot air for many times to gradually reduce the moisture of the wet fiber layer to meet the dryness requirements and make non-woven fabrics.

[0005] 3. Use penetrating drum: In a relatively closed box, the wet fiber layer is attached to a porous drum, and dry hot air is blown into the box. The fan in the drum is used to extract the hot and humid air that has passed through the wet fiber layer. After repeated action of multiple drums, the moisture content of the fiber layer is gradually reduced, and non-woven fabric is made after reaching a certain dryness.

[0006] The above drying methods each have their own advantages and disadvantages. Especially when producing high-weight non-woven fabrics and increasing production speed and capacity, the wet fiber layer has a large water content, which makes drying difficult and consumes a lot of heat energy, which brings obstacles to the production of wet non-woven fabrics. The shortcomings of the current drying methods in the production process of wet non-woven fabrics are as follows:

[0007] 1. Drying drum heating: It adopts surface heat conduction heating. During the heating process, the wet fiber layer transfers heat from the joint between the drying drum and the wet fiber layer to the outside. Since the diameter of the drying drum cannot be too large, in order to achieve the dryness requirements, it needs to go through multiple transfers and drying. The water molecules in the fiber layer attached to the surface of the drying drum are not easy to volatilize, and the water-containing hot air gathered between the drying drums is not easy to be discharged, resulting in a decrease in thermal efficiency. Especially when producing high gram weight, the number of drying drums must be increased to achieve the drying purpose. Not only the length of the equipment increases, but also the investment cost and energy consumption increase.

[0008] 2. Oven heating: Since the wet fiber layer is always moving along the conveyor net, the incoming hot air only blows to the surface of the wet fiber layer, and the bottom layer of the wet fiber attached to the conveyor net has no direct contact with the hot dry air, resulting in a temperature difference. In addition, the heat exchange efficiency between the hot dry air and the wet fiber layer is relatively low. Especially when producing high-weight products and increasing the vehicle speed, in order to achieve the drying effect, the drying distance must be extended, resulting in a long oven length, increased floor space and equipment investment, reduced thermal efficiency, and increased production costs.

[0009] 3. Penetration drum heating: During penetrating drum drying, the wet fiber layer and the breathable drum are directly attached, and the air is heated by the heat exchanger and directly enters the closed box. The penetrating drum is directly placed in the box, and the suction fan inside the drum sucks the hot dry air in the box through the wet fiber layer. The wet air sucked out by the fan is partially discharged, and part of it flows back to the heat exchanger, and is heated again and blown back to the box. There are multiple penetrating drums built into the box, and each drum has the same working principle. After multiple positive and negative blowing and suction actions, the water molecules in the wet fiber layer are discharged. However, when the moisture content of the wet fiber layer is high, the air permeability is very poor, especially when producing high-weight products, the air resistance is particularly large, and it is difficult for the suction fan to extract the wet air, resulting in a large amount of wet air volatilizing in the box, and the humidity gradually increases, affecting the drying efficiency. In addition, since there are multiple penetrating drums built into the box, the resistance of the fiber layer is different when each drum is sucked, and it is difficult to accurately adjust the suction air volume and return air ratio, resulting in the air dryness in the box being difficult to control. If too much is sucked, the energy consumption will increase, and if too little is sucked, the drying requirements cannot be met, affecting the drying efficiency and cost.

[0010] In summary, each drying method has certain shortcomings. How to solve the defects of slow drying speed and high heat energy consumption in the production process of wet non-woven fabrics is the key problem currently faced in the production process of wet non-woven fabrics. Summary of the invention

[0011] The utility model aims to solve the problems in the prior art and provide a drying device for a high-speed and high-weight wet-laid non-woven fabric production line.

[0012] The specific technical solutions adopted by this utility model are as follows:

[0013] The utility model provides a drying device for a high-speed and high-weight wet non-woven fabric production line, which comprises a multi-stage combined drying device arranged in sequence along a wet non-woven fabric conveying path, and the wet non-woven fabric passes through each stage of the combined drying device step by step; each stage of the combined drying device comprises a plurality of drying cylinders for heating the wet non-woven fabric and a suction drying device, and in the wet non-woven fabric conveying path of each stage of the combined drying device, the wet non-woven fabric first passes around the outer surfaces of each drying cylinder in an alternating manner of the front and back sides, and then passes through a hot air drying area of ​​the suction drying device, the suction drying device comprises a hot air outlet and a suction port, and the hot air outlet and the suction port are respectively arranged on the front and back sides of the wet non-woven fabric in the hot air drying area, so that the hot air blown out of the hot air outlet penetrates the wet fiber layer of the wet non-woven fabric to form hot and humid air and is extracted through the suction port.

[0014] Preferably, the suction drying equipment is a suction cylinder, which includes a cylinder body, a suction duct and a heat exchanger; air holes are evenly arranged on the cylinder surface of the cylinder body, and the two end surfaces of the cylinder body are closed, thereby forming a breathable cylinder structure for winding wet non-woven fabrics; the suction duct extends from the outside of the breathable cylinder structure into the inside of the cylinder body and the suction port is located inside the cylinder body; the cross-section of the heat exchanger is arc-shaped, and it surrounds the outer cylinder surface of the breathable cylinder structure in a semi-wrapped form, and hot air outlets are distributed on the side of the outer cylinder surface of the heat exchanger facing the breathable cylinder structure; the area on the outer cylinder surface or inner cylinder surface of the cylinder body that is not wrapped with the heat exchanger is also provided with an arc-shaped closing plate with a consistent curvature, and the arc-shaped closing plate blocks the external air from entering the cylinder through the area not wrapped with the heat exchanger during the suction process.

[0015] Preferably, in the multi-stage combined drying equipment, the outer diameter of the cylinder body in all suction cylinders is kept the same as the outer diameter of all drying cylinders.

[0016] Preferably, the suction drying equipment is a suction platform, which includes a flat net conveying mechanism, a suction device and a heat exchanger; the flat net conveying mechanism drives the flat net to run through a driving roller and then drives the wet fiber layer of the wet non-woven fabric to move close to the flat net, the suction device and the heat exchanger are respectively arranged on the upper and lower sides of the flat net, and a hot air outlet is distributed on the side of the heat exchanger facing the wet fiber layer on the flat net. The hot air blown out from the hot air outlet penetrates the wet fiber layer on the flat net to form hot and humid air and is extracted by the suction device.

[0017] Preferably, the heat exchanger is provided with an adjustment plate for adjusting the size of the hot air outlet area.

[0018] Preferably, the number of drying cylinders in the multi-stage combined drying equipment arranged in sequence along the conveying direction of the wet non-woven fabric decreases gradually.

[0019] Preferably, the total number of stages of the combined drying equipment is 2 to 10, and the number of drying cylinders included in each stage of the combined drying equipment is 2 to 20.

[0020] Preferably, the last stage of combined drying equipment is followed by a plurality of drying cylinders without suction drying equipment.

[0021] Preferably, in the multi-stage combined drying equipment, the drying drum in each stage of the combined drying equipment can independently control the drying drum temperature and the drying drum speed, and the suction drying equipment in each stage of the combined drying equipment can independently control the conveying speed, the heat exchanger outlet air temperature, and the suction air volume.

[0022] Preferably, between any two adjacent stages of combined drying equipment along the conveying direction of the wet non-woven fabric, the suction port of the suction drying equipment relatively located downstream is connected to the air inlet of the suction drying equipment relatively located upstream through a pipe; the suction port of the suction drying equipment located most upstream is connected to the hot side channel of the heat exchange equipment through a return air duct, and the cold side channel of the heat exchange equipment is connected to the air inlet of the suction drying equipment located most downstream through an air inlet duct, and the heat exchange equipment is used to introduce external air and send it to each stage of suction drying equipment in sequence after heat exchange with the humid hot air in the hot side channel.

[0023] Compared with the prior art, the utility model has the following beneficial effects:

[0024] The utility model adopts a plurality of drying drums and a suction drying device to form a first-level combined drying device, and then connects the multi-stage combined drying devices in series to improve the overall drying efficiency by alternating heating and suction dehumidification. The utility model can heat the wet fiber layer through the drying drum according to the weight range and vehicle speed of the product, combined with the different water content of the hot air in each drying area, and after the water molecules become active and turn into water vapor, use the suction drying device to extract the water vapor, and then send the wet fiber layer to the next-level combined drying device to continue using the drying method of drying drum heating + suction drying device suction. In the process of repeated step-by-step drying, the temperature of the drying drum and the suction air volume of each stage can be controlled, and the water molecules generated by vaporization in the wet fiber layer can be extracted in time to improve the drying efficiency, thereby increasing the production capacity of wet non-woven fabrics and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the drying device in Example 1;

[0026] Figure 2 It is a schematic diagram of the suction cylinder structure in Example 1;

[0027] Figure 3 It is a schematic diagram of the heat exchange equipment in Example 1;

[0028] Figure 4 It is a structural schematic diagram of the drying device in Example 2;

[0029] Figure 5 This is a schematic diagram of the suction platform structure in Example 2. DETAILED DESCRIPTION

[0030] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific implementations. The technical features of each implementation of the present invention can be combined accordingly without conflicting with each other.

[0031] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the utility model can be combined accordingly without conflicting with each other.

[0032] In the description of the present utility model, it is necessary to understand that when an element is considered to be "connected" to another element, it can be directly connected to another element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0033] In a preferred embodiment of the utility model, a drying device for a high-speed and high-weight wet non-woven fabric production line is provided, the drying device comprising a multi-stage combined drying device arranged in sequence along the wet non-woven fabric conveying path, the wet non-woven fabric passes through each stage of the combined drying device step by step, and each stage of the combined drying device can perform a drying process on the wet fiber layer corresponding to the wet non-woven fabric. Each stage of the combined drying device includes a plurality of drying cylinders for heating the wet non-woven fabric and a suction drying device, and in the wet non-woven fabric conveying path of each stage of the combined drying device, the wet non-woven fabric first passes around the outer surface of each drying cylinder in an alternating manner of the front and back sides, and then passes through the hot air drying area of ​​the suction drying device.

[0034] It should be noted that the drying drum used in the present invention is an existing device, which has a heat source inside and can control the surface heating temperature. The wet fiber layer of the wet non-woven fabric can be wrapped around the outer surface of the drying drum at a certain wrapping angle, and the temperature of the drying drum surface will be transferred to the wet fiber layer to heat it.

[0035] It should be noted that the suction drying equipment refers to equipment that dries the wet fiber layer of the wet non-woven fabric by blowing out hot air and suctioning. The specific form is not limited, and the area used to dry the wet fiber layer of the wet non-woven fabric is called the hot air drying area. However, no matter what form of the suction drying equipment, the suction drying equipment should have a hot air outlet and a suction port, which are respectively arranged on the front and back sides of the wet non-woven fabric in the hot air drying area, so that the hot air blown out of the hot air outlet penetrates the wet fiber layer of the wet non-woven fabric to form hot and humid air and is sucked out by the suction port.

[0036] In an embodiment of the utility model, one form of the suction drying device is a suction cylinder, which includes a cylinder body, a suction air duct and a heat exchanger. The cylinder surface of the cylinder body is evenly provided with air holes, and the two end faces of the cylinder body are closed, thereby forming a breathable cylinder structure for winding the wet non-woven fabric. The specific material of the above-mentioned suction cylinder can be adjusted according to actual needs. In an embodiment of the utility model, the cylinder body can be made of a cylinder made of cast iron or rolled plate with evenly opened holes, or it can be made of a steel wire mesh or a nylon mesh wrapped around a supporting drum frame. The wet fiber layer of the wet non-woven fabric can fit around the outer cylinder surface of the breathable cylinder structure at a certain wrapping angle. The suction air duct extends from the outside of the breathable cylinder structure into the inside of the cylinder body and the suction port is located inside the cylinder body. The cross-section of the heat exchanger is arc-shaped, and it surrounds the outer cylinder surface of the breathable cylinder structure in a semi-wrapped form. The heat exchanger is provided with hot air outlets on one side of the outer cylinder surface of the breathable cylinder structure. A certain interval is maintained between the heat exchanger and the outer surface of the breathable cylinder structure so that the wet fiber layer can pass smoothly, but the interval should not be too large to prevent the hot air from penetrating the wet fiber layer. The specific wrapping angle of the heat exchanger can be designed according to actual needs, but the area on the outer surface or inner surface of the cylinder body that does not wrap the heat exchanger is also provided with an arc-shaped closing plate with the same curvature, and the arc-shaped closing plate blocks the external air from entering the cylinder through the area that does not wrap the heat exchanger during the suction process. The hot air outlet on the heat exchanger also corresponds to the air inlet. A heat source is provided inside the heat exchanger. The air entering from the air inlet can be heated to the required temperature by the heat source with controllable temperature, and then blown out from the hot air outlet. Under the suction action of the suction duct inside the breathable cylinder structure, the hot air will penetrate the wet fiber layer, and enter the inside of the cylinder body through the air holes on the cylinder surface of the cylinder body, and be discharged from the suction port. In this process, a large amount of water vapor originally generated by heating in the wet fiber layer will be quickly discharged with the hot air, so as to avoid the accumulation of these water vapors in the wet fiber layer and reduce the drying efficiency.

[0037] In addition, when using suction drying equipment in the form of a suction cylinder, the outer diameter of the cylinder body of all suction cylinders in the multi-stage combined drying equipment is preferably kept the same as the outer diameter of all drying cylinders, so as to ensure that the wet fiber layer can be transported smoothly and at a uniform speed during the conveying process, reduce the control difficulty of the entire equipment, and improve the qualified rate of finished products.

[0038] In addition, in another embodiment of the utility model, another form of the suction drying device is a suction platform, which includes a flat net conveying mechanism, a suction device and a heat exchanger. The flat net conveying mechanism belongs to a common device in the prior art, which drives the flat net to run through a driving roller and then drives the wet fiber layer of the wet non-woven fabric to move closely against the flat net. The above-mentioned flat net can be made of materials such as a high-temperature resistant resin net or a metal wire net. The heat exchanger and the suction device are arranged on the upper and lower sides of the flat net. In principle, the suction device and the heat exchanger can be arranged on the upper and lower sides of the flat net, and the specific orientation is not limited. However, considering that the wet fiber layer moves forward on the conveying net, the hot air from top to bottom can press the fiber layer to prevent the fiber layer from floating and slipping. Therefore, it is best that the suction device is below the flat net and the heat exchanger is arranged above the flat net. The heat exchanger located above the flat net is provided with a hot air outlet on the side facing the wet fiber layer on the flat net. The hot air blown out from the hot air outlet penetrates the wet fiber layer on the flat net from top to bottom to form humid hot air and is extracted by the suction device.

[0039] In the embodiment of the utility model, in the above-mentioned suction drying equipment in the form of the suction cylinder and the suction platform, an adjustment plate for adjusting the size of the hot air outlet area can be added to the heat exchanger. The adjustment plate can be moved to adjust the coverage area, and the hot air outlet in the coverage area is blocked, so that the hot air cannot be directly blown to the wet fiber layer, thereby adjusting the hot air outlet area.

[0040] In the above-mentioned drying device of the utility model, by sequentially arranging multi-stage combined drying equipment along the conveying direction of the wet non-woven fabric, an alternating drying process of drying drum heating and hot air suction and dehumidification is realized. In each alternating link, the wet fiber layer is first heated by the drying drum, and after the water molecules become active and easily turn into water vapor, the water vapor in the wet fiber layer is extracted by a suction drying drum or a suction platform under the blowing of hot air, and the humid hot air is quickly discharged, thereby avoiding the problem of decreased thermal efficiency caused by the water molecules in the wet fiber layer attached to the surface of the drying drum being difficult to volatilize and the water-containing hot air accumulated between the drying drums being difficult to discharge.

[0041] Moreover, in the embodiment of the utility model, in the multi-stage combined drying equipment, the drying drum in each stage of the combined drying equipment can finally independently control the drying drum temperature and the drying drum speed, and the suction drying equipment in each stage of the combined drying equipment can independently control the conveying speed, the heat exchanger air outlet temperature, and the suction air volume. Therefore, in each stage of the combined drying equipment, the drying drum temperature, the wet fiber layer surface temperature, the hot air temperature, and the suction air volume can be optimally controlled according to the current wet fiber layer state, so as to ensure that the water molecules in the wet fiber layer can be extracted as soon as possible, thereby improving the drying efficiency.

[0042] Based on the above drying equipment of the utility model, the corresponding control parameters in each level of combined drying equipment can be optimized and adjusted according to the actual situation. Since most of the wet non-woven fabrics do not use the method of squeezing and dehydration in order to ensure the bulkiness of the product, the moisture content of the wet fiber layer coming out of the wet former is particularly high, generally only about 20-25% dryness, and the air permeability of the fiber layer in the wet state is very low, only about 30-40% in the dry state. The air permeability of the wet non-woven fabric produced under the high-speed and high-weight process is even lower, only 20-30% in the dry state. Therefore, taking the first-level combined drying equipment as an example, the utility model needs to first use a drying cylinder to directly attach the wet fiber layer to the drying cylinder for heating. After several front and back heating, the temperature of the fiber layer reaches the vaporization temperature of water molecules (about 80°C), so that the water molecules in the fiber layer are fully active and easy to vaporize. Then, a suction drying device is used to heat it, exhaust air and dehumidify it. Taking the suction drying equipment in the form of a suction cylinder as an example, the wet fiber layer heated by multiple drying cylinders is further sent into a suction cylinder with the same diameter as the drying cylinder and a large number of circular or rectangular air holes on the surface. A suction air duct is fixed in the middle of the cylinder, and an adjustable limit baffle is used to control the suction area and the fiber layer wrapping area. When the wet fiber layer passes through the suction cylinder, the heat exchanger is wrapped on the outside, and the hot air outlet area of ​​the heat exchanger matches the inner suction area. Then, the hot air passing through the heat exchanger can be sucked through the fiber layer to the inside of the cylinder by the suction fan, and the hot and humid air is discharged by the suction air duct. Of course, the suction cylinder can also be changed into a suction platform, which can also achieve the same effect.

[0043] In this drying process, taking the suction drying equipment in the form of a suction cylinder as an example, the combined drying equipment of the drying cylinder and the suction cylinder can be combined according to the gram weight range of the product and the production speed. The total number of stages of the combined drying equipment is preferably 2 to 10, and the number of drying cylinders contained in each stage of the combined drying equipment is preferably 2 to 20. The number of drying cylinders in the multi-stage combined drying equipment arranged in sequence along the conveying direction of the wet non-woven fabric is gradually decreasing, that is, the number of drying cylinders is in the form of more first and less later, the number of drying cylinders in the most upstream combined drying equipment is the largest, and the number of drying cylinders in the most downstream combined drying equipment is the smallest, and the intermediate can be continuously or discontinuously decreasing. In each stage of the combined drying equipment, the control parameters of each device can be adjusted based on the moisture and dryness dried out each time. It is preferred that the temperature and humidity detection sensor is used to detect the humidity and temperature data of the wet fiber layer entering the suction cylinder in real time, and automatically adjust the rotation speed and temperature of the drying cylinder to ensure that the surface temperature of the wet fiber layer entering the subsequent suction cylinder is in the optimal moisture vaporization temperature range. In the suction cylinder, the suction power is provided by the suction fan connected to the suction duct. The suction fan adopts a variable speed motor and can select the speed according to the air permeability to control the air volume. Each level of combined drying equipment can adjust the control parameters according to the moisture status of the wet fiber layer. Finally, the drying cylinder is used to adjust the dryness to meet the product requirements. The hot air temperature in the suction cylinder should be close to the temperature of the wet fiber layer. It does not have to be exactly the same. It can be slightly higher or lower, but the deviation is preferably within the range of 5 to 10°C. The role of the hot air is to ensure that the temperature of the wet fiber layer is maintained as much as possible during the air extraction and dehumidification process, so that it can be maintained in the optimal moisture vaporization temperature range as much as possible.

[0044] In addition, in order to reduce the overall energy consumption level of the drying device, between any two adjacent combined drying devices along the conveying direction of the wet non-woven fabric, the suction port of the suction drying device located relatively downstream is connected to the air inlet of the suction drying device located relatively upstream through a pipeline; the suction port of the suction drying device located most upstream is connected to the hot side channel of the heat exchange device through a return air duct, and the cold side channel of the heat exchange device is connected to the air inlet of the suction drying device located most downstream through an air inlet duct, and the heat exchange device is used to introduce external air and exchange heat with the hot and humid air in the hot side channel, and then send it to each level of suction drying equipment in turn, and the hot and humid air after exchange is directly discharged and no longer used. The heat exchange device used in the embodiment of the utility model can adopt a clamp-tube heat exchanger. Therefore, each time the hot air extracted from the previous stage can be used as the inlet air of the next heat exchanger. The inlet air volume is determined according to the suction air volume, and the excess is discharged. The humid hot air extracted from the first-stage combined drying equipment that enters the drying area of ​​the wet fiber layer is completely discharged after heat exchange with the clamp-tube heat exchanger, and the air heated by the heat exchange is used as the inlet air of the last-stage combined drying equipment. In this way, the thermal energy can be fully utilized, the temperature of the inlet air can be guaranteed, the temperature of the wet fiber layer can be prevented from being lowered during the suction process, and energy consumption can be reduced.

[0045] In addition, it should be noted that in the above drying device of the utility model, in addition to the multi-stage series-connected combined drying equipment, multiple drying cylinders without suction drying equipment can also be connected after the last stage of the combined drying equipment. The purpose of these drying cylinders is to heat and dry the wet nonwoven fabric again before it is rolled up to ensure the drying effect.

[0046] In another embodiment of the present invention, a high-speed high-weight wet nonwoven fabric drying method using the above-mentioned drying device is also provided, and the specific method is as follows:

[0047] The wet fiber layer produced by the wet process is input into the multi-stage combined drying equipment in the drying device through a conveying network; in each stage of the combined drying equipment, the surface temperature of each drying cylinder is controlled so that the wet fiber layer is gradually heated up under the heat provided by the drying cylinder, and the wet fiber layer is sent to the suction drying equipment after reaching the vaporization temperature of water molecules. The suction drying equipment blows hot air to the wet fiber layer through the hot air outlet. In the process of hot air penetrating the wet fiber layer, the internal water vapor is taken out together to form hot and humid air which is extracted from the suction port. After the wet fiber layer completes one stage of drying, it is continuously sent to the next stage of the combined drying equipment for the next stage of drying, so that the dryness of the wet fiber layer is continuously improved in this reciprocating manner.

[0048] And in the multi-stage combined drying equipment arranged in sequence along the conveying direction of the wet non-woven fabric, since the moisture content of the wet fiber layer is constantly decreasing, but the air permeability is constantly increasing, the overall temperature and air volume control principle is: in the multi-stage combined drying equipment, the surface temperature of the drying cylinder increases step by step, the temperature of the wet fiber layer fed into the suction drying equipment increases step by step, the temperature of the hot air blown out by the suction drying equipment increases step by step and is not lower than the temperature of the wet fiber layer required to penetrate (to avoid causing the wet fiber layer to be cooled due to exhaust), and the suction air volume of the suction drying equipment increases step by step.

[0049] In the embodiment of the utility model, in the multi-stage combined drying equipment arranged in sequence along the conveying direction of the wet non-woven fabric, the overall temperature control range is as follows: the surface temperature of the drying drum increases step by step within the range of 90 to 130°C, the temperature of the wet fiber layer fed into the suction drying equipment increases step by step within the range of 70 to 110°C, the temperature of the hot air blown out by the suction drying equipment increases step by step within the range of 80 to 110°C and is not lower than the temperature of the wet fiber layer required to penetrate, and the suction air volume of the suction drying equipment is 5m 3 / s~8m 3 / s range and increases gradually.

[0050] In addition, from the perspective of heat recovery and energy saving, along the conveying direction of the wet non-woven fabric, the hot and humid air extracted by the suction drying equipment located downstream through the suction port is conveyed to the suction drying equipment located upstream, and is blown out from the hot air outlet after the temperature and air volume are modulated; the hot and humid air extracted by the suction drying equipment located most upstream enters the hot side channel of the heat exchange equipment as return air, and the external air is introduced into the cold side channel of the heat exchange equipment to exchange heat with the hot and humid air, and the hot and humid air after heat exchange is directly discharged, and the external air after heat exchange is sent to the suction drying equipment located most downstream.

[0051] The present invention will now demonstrate the specific implementation and technical effects of the above-mentioned drying device and drying method through several embodiments.

[0052] Example 1

[0053] In this embodiment, each stage of the combined drying equipment in the drying device adopts a suction drying device in the form of a suction drying cylinder, and a total of three stages of combined drying equipment and a fourth stage of pure drying without exhaust equipment are set. The specific form is as follows Figure 1 Each stage of the combined drying equipment includes a plurality of drying cylinders 2 for heating the wet nonwoven fabric and a suction cylinder. Figure 2 As shown, the suction cylinder includes a cylinder body 3, a suction air duct 10 and a heat exchanger 4. The cylinder surface of the cylinder body 3 is evenly provided with air holes, and the two end surfaces of the cylinder body are closed, thereby forming a breathable cylinder structure for winding wet non-woven fabrics. The suction air duct 10 extends from the outside of the breathable cylinder structure into the inside of the cylinder body 3, and the suction port is located inside the cylinder body 3. The cross-section of the heat exchanger 4 is arc-shaped, and it surrounds the outer cylinder surface of the breathable cylinder structure in a semi-wrapped form. The heat exchanger is provided with hot air outlets on the side of the outer cylinder surface of the breathable cylinder structure. The area on the inner cylinder surface of the cylinder body that does not wrap the heat exchanger is also provided with an arc-shaped closing plate 11 with a consistent curvature, and the arc-shaped closing plate 11 prevents external air from entering the cylinder through the area that does not wrap the heat exchanger during the suction process.

[0054] In the wet non-woven fabric conveying path of each level of the combined drying equipment, the wet fiber layer of the wet non-woven fabric first passes around the outer surface of each drying cylinder 2 in an alternating manner of front and back, and then passes through the hot air drying area clamped between the cylinder body 3 and the heat exchanger 4 in the suction cylinder. The suction cylinder has a hot air outlet and a suction port, and the hot air outlet and the suction port are respectively arranged on the front and back sides of the wet non-woven fabric in the hot air drying area, so that the hot air blown out of the hot air outlet penetrates the wet fiber layer of the wet non-woven fabric to form humid hot air and is extracted from the suction port.

[0055] In the drying device, the first-stage combined drying equipment includes 8 drying cylinders 2, namely A1 to A8, and also includes a suction cylinder, which is denoted as 1# suction cylinder. The heat exchanger 4 in the 1# suction cylinder is denoted as F1, and the suction power in the suction cylinder is provided by the M1 suction fan. The second-stage combined drying equipment includes 8 drying cylinders 2, namely B1 to B8, and also includes a suction cylinder, which is denoted as 2# suction cylinder. The heat exchanger 4 in the 2# suction cylinder is denoted as F2, and the suction power in the suction cylinder is provided by the M2 suction fan. The third-stage combined drying equipment includes 6 drying cylinders 2, namely C1 to C8, and also includes a suction cylinder, which is denoted as 3# suction cylinder. The heat exchanger 4 in the 3# suction cylinder is denoted as F3, and the suction power in the suction cylinder is provided by the M3 suction fan. In addition, after the three-stage combined drying equipment, six drying cylinders 2 are arranged, namely D1 to D6, but without a suction cylinder, for further drying. Finally, after D6 is dried, a dry fiber layer 5 is formed, i.e., the wet nonwoven fabric after final drying.

[0056] In addition, in order to save energy, between any two adjacent combined drying devices along the conveying direction of the wet nonwoven fabric, the suction port of the suction cylinder located downstream is connected to the air inlet of the suction cylinder located upstream through a pipeline. Figure 3 As shown, this embodiment adopts a clamp-tube heat exchanger as the heat exchange device 7. The suction port of the suction cylinder located at the most upstream is connected to the hot side channel of the heat exchange device through the return air duct, and the cold side channel of the heat exchange device is connected to the air inlet of the suction cylinder located at the most downstream through the air inlet duct. The heat exchange device is used to introduce external air and exchange heat with the hot and humid air in the hot side channel, and then send it to each level of suction cylinder in sequence.

[0057] The specific technical parameters, the configuration of the drying drum and the suction drying drum, and the wet nonwoven fabric drying process of this embodiment are introduced in detail below.

[0058] ①Technical parameters: Product weight: 60g / ㎡ Speed: 400M / min

[0059] The dryness of the product entering the drying system is 25% and the dryness of the product leaving the drying system is 95%.

[0060] Wet fiber layer air permeability: 300L / ㎡·S

[0061] Dry fiber layer air permeability: 850L / ㎡·S

[0062] ②Drying cylinder and suction drying cylinder configuration:

[0063] Total number of configurations: 28 Φ1500mm drying cylinders, 3 Φ1500mm suction cylinders, including:

[0064] First stage: 8 Φ1500mm drying cylinders + 1 Φ1500mm suction cylinder; second stage: 8 Φ1500mm drying cylinders + 1 Φ1500mm suction cylinder; third stage: 6 Φ1500mm drying cylinders + 1 Φ1500mm suction cylinder; last stage: 6 Φ1500mm drying cylinders.

[0065] ③Wet non-woven fabric drying process:

[0066] a. Introduce the wet fiber layer into the first group of 8 drying cylinders. When entering, the wet fiber layer has a dryness of 25% and a surface temperature of 20°C. The surface temperature of the drying cylinders is set to 80-100°C. When leaving the first group of drying cylinders, the surface temperature of the wet fiber layer is 70-80°C and the dryness is 28%.

[0067] b. The fiber layer that has passed through the first set of drying cylinders is introduced into the first suction drying cylinder with a suction air volume of 5m 3 / S, hot air inlet temperature is 80-85℃, when leaving the first suction drying cylinder, the surface temperature of the wet fiber layer is 80-82℃, and the dryness is 32-35%.

[0068] c. The fiber layer then enters the second set of drying cylinders, which are 8 in number and have a surface temperature of 100-110°C. When the fiber layer exits the second set of drying cylinders, its surface temperature is 95-100°C and its dryness is 40-42%.

[0069] d. When the fiber layer enters the second suction drying cylinder, the hot air inlet temperature is 95-105℃ and the suction air volume is 6m 3 / S, the surface temperature of the fiber layer of the second suction drying cylinder is 100-105°C, and the dryness is 60-65%.

[0070] e. The fiber layer enters the third group of drying cylinders again. There are 6 drying cylinders and the surface temperature of the drying cylinders is 110-120°C. When the fiber layer exits the third group of drying cylinders, the surface temperature is 105-110°C and the dryness is 70-75%.

[0071] f. The fiber layer then enters the third suction drying cylinder, with the hot air inlet temperature of 100-110℃ and the suction air volume of 8m 3 / S, when the third suction drying cylinder comes out, its surface temperature is 100-105℃ and the dryness is 85-90%.

[0072] g. The fiber layer then enters the fourth group of drying cylinders, which has 6 drying cylinders and a surface temperature of 120-130°C. When the fiber layer exits the fourth group of drying cylinders, the surface temperature is 105-110°C and the dryness is 95-97%.

[0073] The technical parameters of the drying device in this embodiment are compared with those of the existing practices of using a drying cylinder alone, a drying oven alone, and a penetrating drum alone. When the four methods achieve the same production volume, the drying device in this embodiment has obvious advantages in terms of floor space and energy consumption, and its production efficiency is also significantly improved.

[0074] Table 1 Comparison results of technical parameters of Example 1

[0075]

[0076] Example 2

[0077] In this embodiment, each stage of the combined drying equipment in the drying device adopts a suction drying device in the form of a suction platform, and a total of two stages of combined drying equipment and a third stage of pure drying without suction equipment are set. The specific form is as follows Figure 4 Each stage of the combined drying equipment includes a plurality of drying cylinders 2 for heating the wet nonwoven fabric and a suction platform. Figure 5 As shown, each suction platform includes a flat net conveying mechanism 9, a suction device 8 and a heat exchanger 12. The flat net conveying mechanism 9 drives the flat net to move through a driving roller, and then drives the wet fiber layer of the wet non-woven fabric to move closely against the flat net. The suction device 8 and the heat exchanger 12 are respectively arranged on the upper and lower sides of the flat net. The heat exchanger 12 is provided with hot air outlets on one side facing the wet fiber layer on the flat net. The hot air blown out from the hot air outlets penetrates the wet fiber layer on the flat net to form hot and humid air and is extracted by the suction device 8.

[0078] In the wet non-woven fabric conveying path of each level of the combined drying equipment, the wet fiber layer of the wet non-woven fabric first passes around the outer surface of each drying cylinder 2 in an alternating manner of front and back, and then passes through the hot air drying area clamped between the flat mesh conveying mechanism 9 and the heat exchanger 12 in the suction platform. After the heat exchanger 12 heats and modulates the air input from the air inlet, hot air is blown out from the hot air outlet according to a preset air volume. The hot air penetrates the wet fiber layer of the wet non-woven fabric to form humid hot air and is extracted from the suction port of the suction device 8.

[0079] In the drying device, the first-stage combined drying equipment includes 8 drying cylinders 2, namely A1 to A8, and also includes a suction platform, denoted as 1# suction platform, the heat exchanger 4 in the 1# suction platform is denoted as e1, and the suction device 8 is denoted as d1; the second-stage combined drying equipment includes 8 drying cylinders 2, namely B1 to B8, and also includes a suction platform, denoted as 2# suction platform, the heat exchanger 4 in the 2# suction platform is denoted as e2, and the suction device 8 is denoted as d2. The suction power in the two suction platforms is provided by the suction fan M. In addition, after the three-stage combined drying equipment, 6 drying cylinders 2 are set, namely C1 to C6, but no suction platform is set, for further drying. Finally, after C6 is dried, a dry fiber layer 5 can be formed, that is, the wet non-woven fabric after final drying.

[0080] In addition, in order to save energy, between any two adjacent combined drying devices along the conveying direction of the wet non-woven fabric, the suction port of the suction platform located relatively downstream is connected to the air inlet of the suction platform located relatively upstream through a pipe. This embodiment also uses a clamp-tube heat exchanger as the heat exchange device 7, the suction port of the suction platform located at the most upstream is connected to the hot side channel of the heat exchange device through the return air duct, and the cold side channel of the heat exchange device is connected to the air inlet of the suction platform located at the most downstream through the air inlet duct. The heat exchange device 7 is used to introduce external air and exchange heat with the hot and humid air in the hot side channel, and then send it to each level of suction platform in turn.

[0081] The specific technical parameters, the configuration of the drying drum and the suction platform, and the wet nonwoven fabric drying process of this embodiment are introduced in detail below.

[0082] ①Technical parameters: Product weight: 80g / ㎡ Speed: 300M / min

[0083] The dryness of the drying system is 22% and the dryness of the drying system is 95%.

[0084] Air permeability of wet fiber layer: 200L / ㎡·S

[0085] Air permeability of dry fiber layer: 600L / ㎡·S

[0086] ②Drying cylinder and suction drying cylinder configuration:

[0087] The first stage: 8 Φ1800mm drying cylinders + 1 suction platform with multiple suction ports; the second stage: 8 Φ1500mm drying cylinders + 1 suction platform with multiple suction ports; the last stage: 6 Φ1800mm drying cylinders.

[0088] ③Wet non-woven fabric drying process:

[0089] a. Introduce the wet fiber layer into the first group of 8 drying cylinders. When entering, the wet fiber layer has a dryness of 22% and a surface temperature of 12°C. The surface temperature of the drying cylinders is set to 90-110°C. When exiting the first group of drying cylinders, the surface temperature of the wet fiber layer is 70-80°C and the dryness is 30-35%.

[0090] b. The fiber layer after the first set of drying cylinders is introduced into the first suction platform. There is a heat exchanger above the platform. The hot air temperature out of the exchanger is 80-100 degrees Celsius. The air volume of the platform suction fan is 3-4m 3 / S, the surface temperature of the fiber layer at the first suction platform is 85-90°C, and the dryness is 50-55%.

[0091] c. The fiber layer is introduced into the second set of drying cylinders, the number of which is 8, and the surface temperature of the drying cylinders is 110-120°C. When the fiber layer exits the second set of drying cylinders, its surface temperature is 100-105°C and the dryness is 60-70%.

[0092] d. The fiber layer enters the second set of suction platforms. The air temperature of the heat exchanger above the platform is 100-110℃, and the suction air volume is 6-8m 3 / S, the surface temperature of the second suction platform is 95-100℃, and the dryness is 25-85%.

[0093] e. The fiber layer enters the third group of drying cylinders, there are 6 drying cylinders, the surface temperature of the drying cylinders is 100-120℃, and when the fiber layer exits the third group of drying cylinders, the surface temperature is 100-110℃, and the dryness is >95%.

[0094] The technical parameters of the drying device formed by the combination of the drying cylinder and the suction platform in this embodiment are compared with the drying device formed by the combination of the drying cylinder and the suction cylinder in Example 1. Both have their own advantages and disadvantages when achieving the same production volume, and need to be selected according to the actual application scenario.

[0095] Table 2 Comparison results of technical parameters of Example 2

[0096]

[0097] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A drying device for a high-speed and high-weight wet-laid nonwoven fabric production line, characterized in that: The invention comprises a plurality of combined drying devices arranged in sequence along a conveying path of a wet nonwoven fabric, wherein the wet nonwoven fabric passes through each combined drying device step by step; each combined drying device comprises a plurality of drying cylinders for heating the wet nonwoven fabric and a suction drying device, and in the conveying path of the wet nonwoven fabric of each combined drying device, the wet nonwoven fabric first passes around the outer surfaces of each drying cylinder in an alternating manner of the front and back sides, and then passes through a hot air drying area of ​​the suction drying device, wherein the suction drying device comprises a hot air outlet and a suction port, and the hot air outlet and the suction port are respectively arranged on the front and back sides of the wet nonwoven fabric in the hot air drying area, so that the hot air blown out of the hot air outlet penetrates the wet fiber layer of the wet nonwoven fabric to form humid hot air which is then extracted through the suction port.

2. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to claim 1, characterized in that: The suction drying device is a suction cylinder, which includes a cylinder body, a suction air duct and a heat exchanger; the cylinder surface of the cylinder body is evenly provided with air holes, and the two end surfaces of the cylinder body are closed, so as to form a breathable cylinder structure for winding the wet non-woven fabric; The suction duct extends from the outside of the breathable cylindrical structure into the inside of the cylindrical body, and the suction port is located inside the cylindrical body; the cross-section of the heat exchanger is arc-shaped, and is surrounded by the outer cylinder surface of the breathable cylindrical structure in a semi-wrapped form, and hot air outlets are distributed on the side of the outer cylinder surface of the heat exchanger facing the breathable cylindrical structure; the area on the outer cylinder surface or the inner cylinder surface of the cylindrical body that is not wrapped with the heat exchanger is also provided with an arc-shaped closing plate with the same curvature, which blocks the external air from entering the cylinder through the area not wrapped with the heat exchanger during the suction process.

3. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to claim 2, characterized in that: In the multi-stage combined drying equipment, the outer diameters of the cylinder bodies in all the suction cylinders are kept the same as the outer diameters of all the drying cylinders.

4. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to claim 1, characterized in that: The suction drying equipment is a suction platform, which includes a flat net conveying mechanism, a suction device and a heat exchanger; the flat net conveying mechanism drives the flat net to run through a driving roller and then drives the wet fiber layer of the wet non-woven fabric to move closely against the flat net, the suction device and the heat exchanger are respectively arranged on the upper and lower sides of the flat net, and a hot air outlet is distributed on the side of the heat exchanger facing the wet fiber layer on the flat net. The hot air blown out from the hot air outlet penetrates the wet fiber layer on the flat net to form hot and humid air and is extracted by the suction device.

5. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 2 to 4, characterized in that: The heat exchanger is provided with an adjustment plate for adjusting the size of the hot air outlet area.

6. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 1 to 4, characterized in that: The number of drying cylinders in the multi-stage combined drying equipment arranged in sequence along the conveying direction of the wet non-woven fabric decreases gradually.

7. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 1 to 4, characterized in that: The total number of stages of the combined drying equipment is 2 to 10, and the number of drying cylinders included in each stage of the combined drying equipment is 2 to 20.

8. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 1 to 4, characterized in that: The last stage of combined drying equipment is followed by a plurality of drying cylinders without suction drying equipment.

9. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 1 to 4, characterized in that: In the multi-stage combined drying equipment, the drying drum in each stage of the combined drying equipment can independently control the drying drum temperature and the drying drum speed, and the suction drying equipment in each stage of the combined drying equipment can independently control the conveying speed, the heat exchanger air outlet temperature, and the suction air volume.

10. The drying device for a high-speed and high-weight wet-laid nonwoven fabric production line according to any one of claims 1 to 4, characterized in that: Between any two adjacent stages of combined drying equipment along the conveying direction of the wet non-woven fabric, the suction port of the suction drying equipment relatively located downstream is connected to the air inlet of the suction drying equipment relatively located upstream through a pipeline; the suction port of the suction drying equipment located most upstream is connected to the hot side channel of the heat exchange equipment through a return air duct, and the cold side channel of the heat exchange equipment is connected to the air inlet of the suction drying equipment located most downstream through an air inlet duct, and the heat exchange equipment is used to introduce external air and send it to each stage of suction drying equipment in sequence after heat exchange with the humid hot air in the hot side channel.

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