CN104501560A - Drying device for intelligently regulating internal temperature of tank - Google Patents

Abstract

A drying device for plates, including a box body, a heating zone and a preheating zone are arranged in the box, the preheating zone is set at the front of the heating zone and connected to the heating zone, along the conveying direction of the conveyor belt, the temperature t is set to Function of the distance x from the entrance of the heating zone, t=f(x), in the heating zone, f'(x)<0, f''(x)>0; in the preheating zone, f'(x)>0 , f''(x)>0; where f'(x), f''(x) are the first and second derivatives of f(x), respectively. The present invention can achieve the best drying effect of the plate through the change of the temperature in the box and the change of the increase rate, and can also save energy.

Description

A drying device with intelligent temperature adjustment in the box

technical field

The invention belongs to the field of drying, in particular to a plate drying device, and belongs to the field of F26B drying.

Background technique

The traditional heating and drying method is not highly intelligent and inefficient in the actual production of plates, and the drying effect is not ideal, which cannot meet the actual production needs. Therefore, a highly intelligent drying equipment is needed to ensure that the plates When the internal moisture content changes and the thickness changes, the drying temperature, conveying speed and other parameters are intelligently adjusted to drop to the required range in a short time.

Contents of the invention

In view of the shortcomings of the current prior art, the purpose of the present invention is to provide a plate drying device, which solves the shortcomings of the existing market products such as low intelligence and low efficiency.

In order to achieve the above object, the technical solution of the present invention is as follows: a plate drying device, including a box body, a heating zone and a preheating zone are arranged in the box, and the preheating zone is arranged at the front of the heating zone and connected to the heating zone , along the conveying direction of the conveyor belt, set the temperature t as a function of the distance x from the entrance of the heating zone, t=f(x), in the heating zone, f'(x)<0, f''(x)>0; In the preheating zone, f'(x)>0, f''(x)>0;

Where f'(x), f''(x) are the first and second derivatives of f(x), respectively.

A preferred drying device includes a heating component, a temperature sensor, a programmable controller and a conveyor belt, the conveyor belt passes through the casing, the conveyor belt is provided with a speed control part, and the speed control part is connected to the programmable controller for data, and the programmable controller According to the thickness and moisture content of the plate, the speed of the conveyor belt is controlled by the speed control part; the transmission control method of the conveyor belt is as follows: the reference data stored in the programmable controller is the thickness of the plate, the mass moisture content is S, the heating temperature is T, The transmission speed of the conveyor belt is V when the thickness of the plate is L and the mass moisture content is S, the absolute temperature of heating required is T, and the transmission speed of the conveyor belt is V;

When the thickness of the plate changes to l and the mass moisture content changes to s, the transmission speed of the conveyor belt satisfies the following relationship:

t Keeping the reference temperature T constant, the transmission speed of the conveyor belt changes as follows:

V/v=(s/S) ^c * (l/L) ^d , where c and d are parameters, 1.12<c<1.18, 1.25<d<1.29;

The above formula needs to meet the following conditions: 0.8<s/S<1.2,0.8< l/L<1.2;

In the above formula, temperature T, t is the absolute temperature, the unit is K, which is the average heating temperature in the box, the speed V, the unit of v is m/s, the thickness of the plate is L, l is centimeters, the moisture content s, S is the mass percentage .

Preferably, when the temperature is adjusted, the heating power of the heating components in all the heating zones adopts the same increase or decrease.

Preferably, when the temperature is adjusted, along with the conveying direction of the conveyor belt, the heating power of the heating components in the heating zone increases or decreases gradually.

Preferably, when the temperature is adjusted, the heating power of the heating components in all the preheating zones adopts the same increase or decrease.

Preferably, when the temperature is adjusted, along with the conveying direction of the conveyor belt, the heating power of the heating components in the preheating zone increases or decreases gradually.

Compared with the prior art, the drying device of the present invention has the following advantages:

1) The programmable controller automatically controls the temperature in the box and/or the speed of the conveyor belt to realize the intelligent drying of the board.

2) By setting multiple heating components, the intelligent control of each heating component is realized, thereby realizing the preset distribution of the temperature in the entire box.

3) The infrared heating part is arranged closer to the outlet of the box than the microwave heating part, which can achieve fast drying and good drying effect.

4) The best relationship between control speed and temperature has been obtained through extensive research.

Description of drawings

Fig. 1 is a structural schematic diagram of an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of another embodiment of the present invention.

Fig. 3 is a schematic plan view of the arrangement of temperature sensors in the box of the present invention.

Fig. 4 is a control flow chart of the first operating mode of the present invention.

Fig. 5 is a control flow chart of the second operating mode of the present invention.

Fig. 6 is a control flow chart of the third operating mode of the present invention.

Among them, the box 1, the conveyor belt 2, the heating part 3, the temperature detector 4, the programmable controller 5, the entrance 6, the temperature sensor 7, the plate 8, and the transmission wheel 9.

Detailed ways

It should be noted that the board here refers to board-like materials, such as board-like wood, insulation boards, and the like.

As shown in Figure 1, a drying device for a plate 8 includes a box body 1, a heating component 3, a temperature sensor 7, a programmable controller 5 and a conveyor belt 2, the conveyor belt 2 passes through the box body 1, and the heating component 3 And the temperature sensor 7 is arranged in the casing, and the heating component 3 and the temperature sensor 7 are connected with the programmable controller 5 .

Preferably, the conveyor belt is provided with a speed control unit, and the speed control unit is in data connection with the programmable controller 5, and the programmable controller 5 controls the speed of the conveyor belt through the speed control unit.

Preferably, the speed control unit includes a speed detection unit, and the speed detection unit transmits the detected conveyor belt data to the programmable controller, and the programmable controller adjusts the power of the conveyor belt motor according to the detected data. If the detected speed is lower than the data calculated by the programmable controller, increase the power of the motor, otherwise, reduce the power of the motor. Preferably, the transmission speed of the conveyor belt is adjusted by controlling the rotation speed of the transmission wheel 9 by the motor.

Preferably, there are multiple temperature sensors in the box, and the average temperature is calculated by setting the average value of the measurement data of the multiple temperature sensors.

Preferably, the temperature sensors in the box are arranged in multiple rows vertically perpendicular to the axial direction of the conveyor belt, and the distance between each row is the same.

Preferably, as shown in FIG. 3 , the arrangement of the temperature sensors 7 in adjacent rows is staggered. Through the staggered arrangement, the temperature at different axial positions in the longitudinal direction can be obtained, avoiding only measuring the temperature on the same axis, and ensuring the accuracy of the measurement data.

Preferably, the box body 1 is a cavity with a trapezoidal cross section, the entrance 6 and the exit are provided with electric doors, and the opening of the electric doors can be adjusted. The central controller automatically adjusts the opening of the electric door according to the thickness of the input plate to prevent energy loss caused by excessive opening and achieve the purpose of saving energy.

As preferably, it also includes a temperature detector 4. Of course, the temperature detector just converts the sensor reading and sends it to the PLC. If necessary, the data measured by the temperature sensor can be directly sent to the controller, or set in the controller. Temperature detector, for example Figure 1.

Preferably, the transmission speed of the conveyor belt is 0.4-0.6 m/s.

Preferably, a heating zone is arranged in the box, and along the conveying direction of the conveyor belt, the temperature of the heating zone decreases gradually in a continuous distribution. This allows the board to require less and less heat as it dries more and more, thereby saving energy.

Preferably, along the conveying direction of the conveyor belt, the temperature drop in the heating zone gradually increases. If the temperature t is set as a function of the distance x from the entrance of the heating zone, t=f(x), then in the heating zone, f'(x)<0, f''(x)>0, where f'(x ), f''(x) are the first and second derivatives of f(x) respectively.

t is the average temperature on the cross-section at X position. In practice, the average temperature can be measured by setting multiple temperature sensors, or the average temperature on the cross-section measured by an infrared thermometer.

Experiments have shown that through the above-mentioned temperature change and the change of the increase rate, the best drying effect of the board can be achieved, and energy can also be saved.

The reason why the heating zone is limited here is that there may be a preheating zone in the box, and the heating zone here is the heating zone after the preheating zone. Of course, sometimes the preheating zone is not set, only the heating zone is set.

Preferably, the drying temperature range is 85-120°C.

Preferably, the heating unit 3 includes infrared heating unit and microwave heating unit. In the heating zone, the infrared heating unit is arranged closer to the outlet of the box than the microwave heating unit. The main reason is that the heating principles of the infrared heating part and the microwave heating part are different, because the plate is first heated by microwaves, so that the water molecules in the plate will vibrate and move at the rotational energy level, causing other molecules around them to rub quickly, thus accelerating the water molecules. Evaporate from the inside of the board to the outside, wait until the water molecules basically volatilize to the surface of the board, and then perform baking heating through the infrared heating component, thereby accelerating the drying of the board.

Preferably, a heating part is arranged in the box, and the microwave heating components are distributed within the range from the entrance of the heating part to 1/2-2/3 of the length of the heating part, and the rest of the heating part is allocated with infrared heating components. This setting will achieve the best energy saving and drying effect. Wherein the length of the heating part is the length from the inlet of the heating part to the outlet of the heating part.

In the actual working process, there needs to be an optimal relationship between the speed of the conveyor belt and the heating temperature. If the speed of the conveyor belt is too fast, the heating time will be short, which will affect the heating quality. If the speed of the conveyor belt is too slow, the heating time will be long. Too much energy may be wasted. Similarly, if the heating temperature is too low, the heating quality will be affected, and if the heating temperature is too high, too much energy will be wasted. Therefore, through a large number of experiments, the optimal relationship between heating temperature and transmission speed has been obtained.

The drying device can automatically adjust the heating temperature and the conveying speed of the conveyor belt according to the thickness and humidity of the heating plate. The control method is as follows: Assuming that the plate thickness is L and the mass moisture content is S, the heating temperature in the box is T (absolute temperature), and when the conveying speed of the conveyor belt is V, it means that the drying effect meets certain conditions. The aforementioned plate thickness L, mass moisture content S, speed V and temperature T are referred to as reference thickness, reference humidity, reference speed and reference temperature, ie reference data. The reference data is stored in the programmable controller.

The reference data represent the data of the drying effect satisfying certain conditions. For example, it can meet a certain drying effect, for example, the drying effect is that the moisture content of the board is 0.02%, or when a certain drying effect is achieved, the energy consumption is the least. Of course, the preferred condition is that when a certain drying effect is achieved, the data that consumes the least energy is used as the benchmark data.

The temperature and speed adjusted by the following formula can basically meet the drying effect of certain conditions achieved by the benchmark data.

When the thickness of the plate changes to l and the mass moisture content changes to s, the heating temperature and speed satisfy one of the following three different operating modes:

The first mode: v keeps the reference speed V unchanged, and the heating temperature changes as follows:

t=T*(s/S) ^a *(l/L) ^b , where a and b are parameters, 1.07<a<1.13, 1.15<b<1.20; preferably, a=1.10, b=1.18;

The second mode: t keeps the reference temperature T unchanged, and the transmission speed of the conveyor belt changes as follows:

V/v=(s/S) ^c * (l/L) ^d , where c and d are parameters, 1.12<c<1.18, 1.25<d<1.29; preferably, c=1.15, d=1.27

The third mode: v and t are variable, and the relationship between the heating temperature and the transmission speed of the conveyor belt is as follows:

(v*t)/(V*T)=g*(s/S) ^e *(l/L) ^f , where g, e, and f are parameters, and g satisfies the following formula:

(s/S)/(l/L)>1, 0.95<g<0.98; preferably, g=0.96;

(s/S)/(l/L)<1, 1.04<g<1.08; preferably, g=1.06;

(s/S)/(l/L)=1,0.98<g<1.04; preferably, g=1.02;

Preferably, the third mode selects a set of v and t with the smallest value of ((1-v/V) ² + (1-t/T) ² ); of course, the first set of v and t that meets the requirements can also be selected, You can also randomly select a group from v and t that meet the conditions;

1.10<e<1.15, 1.18<f<1.20; preferably, e=1.13, f=1.19.

Among them, the following conditions need to be met in the formulas of the above three modes: 0.8<s/S<1.2, 0.8< l/L<1.2.

The above formula has been verified through a lot of practice and fully meets the actual drying needs of the board.

In practical applications, multiple sets of reference data are stored in the programmable controller, and then the programmable controller can satisfy 0.8<s/S<1.2,0.8< l/L according to the data input by the user (sheet thickness and sheet moisture content). In the case of <1.2, the appropriate benchmark data is automatically selected as the basis.

Preferably, when there are two or more sets of benchmark data, an interface for user-selected benchmark data can be provided. Preferably, the system can automatically select ((1-s/S) ² + (1-l/L) ² ) with the smallest value.

Only one of the three modes may be stored in the programmable controller, or two or three of them may be stored in the programmable controller.

When there are multiple temperature sensors, the heating temperature is the average temperature measured by multiple temperature sensors in the box.

In the above formula, temperature T and t are absolute temperature in K, velocity V and v in m/s, sheet thickness L and l in cm (centimeters), moisture content s and S in mass percentage.

Preferably, when the temperature is adjusted, the heating powers of the heating components in all the heating zones adopt the same increase or decrease, for example, they all increase by 10% at the same time.

Preferably, when the temperature is adjusted, the heating power of the heating components in all the heating zones adopts different increases or decreases. Along with the conveying direction of the conveyor belt, the heating power of the heating components in the heating zone increases or decreases gradually. For example, along the conveying direction of the conveyor belt, the heating elements in the front are increased by 15%, and the heating elements in the rear are increased by 12%, 11%, and so on.

Preferably, a preheating zone is set in the box, and the preheating zone is set in front of the heating zone and connected to the heating zone. In the preheating zone, along the conveying direction of the conveyor belt, the temperature of the preheating zone increases gradually in a continuous distribution, preferably along the conveying direction of the conveyor belt, the temperature increases gradually. If the temperature t is set as a function of the distance x from the entrance, t=f(x), then in the preheating zone, f'(x)>0, f''(x)>0, where f'(x) , f''(x) are the first and second derivatives of f(x) respectively.

t is the average temperature on the cross-section at X position. In practice, the average temperature can be measured by setting multiple temperature sensors, or the average temperature on the cross-section measured by an infrared thermometer.

Experiments have shown that through the above-mentioned temperature changes and changes in the increase rate, the preheating of the board can achieve very good results, and more than 10% of energy can be saved.

When setting the preheating zone, the temperature T, t in the previous formula is the average temperature including the preheating zone and the heating zone, that is, the temperature of the preheating zone and the heating zone will be considered as an average temperature.

When setting the preheating zone, preferably, when adjusting the temperature, the heating power of the heating components in all the preheating zones adopts the same increase or decrease, for example, all increase by 10% at the same time.

Preferably, when the temperature is adjusted, the heating power of the heating components in the preheating zone adopts different increases or decreases, and along with the conveying direction of the conveyor belt, the heating power of the heating components in the preheating zone increases or decreases gradually. , For example, along the conveying direction of the conveyor belt, the heating components in the front increase by 8%, and the heating components in the rear increase by 10%, 11%, and so on.

Through the change of the above-mentioned increase rate, energy can be greatly saved, compared with the same increase rate, and the accuracy of the drying result can be fully guaranteed. It has been proved by experiments that the error is smaller and the heating effect is better when the amplitude changes.

The invention also discloses a method for realizing the intelligent operation of the drying equipment, which includes the following steps:

1) First store one or more sets of reference data in the programmable controller: the thickness of the plate is L, the mass moisture content is S, the heating temperature in the box is T (absolute temperature), and the transmission speed of the conveyor belt is V;

2) Input the thickness and water content of the plate on the operation interface;

3) According to the thickness and water content of the input plate, the programmable controller can choose to execute or automatically execute (for example, only one operation mode) one of the following three modes:

first mode. v keeps the reference speed V unchanged, and the heating temperature changes as follows:

t=T*(s/S) ^a *(l/L) ^b , where a and b are parameters, 1.07<a<1.13, 1.15<b<1.20; preferably, a=1.10, b=1.18;

Second mode. t Keeping the reference temperature T constant, the transmission speed of the conveyor belt changes as follows:

V/v=(s/S) ^c * (l/L) ^d , where c and d are parameters, 1.12<c<1.18, 1.25<d<1.29; preferably, c=1.15, d=1.27

third mode. v and t are variable, and the relationship between the heating temperature and the conveying speed of the conveyor belt is as follows:

(v*t)/(V*T)=g*(s/S) ^e *(l/L) ^f , where g, e, and f are parameters, and g satisfies the following formula:

(s/S)/(l/L)>1, 0.95<g<0.98; preferably, g=0.96;

(s/S)/(l/L)<1, 1.04<g<1.08; preferably, g=1.06;

(s/S)/(l/L)=1,0.98<g<1.04; preferably, g=1.02;

Preferably, the third mode selects a set of v and t with the smallest value of ((1-v/V) ² + (1-t/T) ² ); of course, the first set of v and t that meets the requirements can also be selected, You can also randomly select a group from v and t that meet the conditions;

1.10<e<1.15, 1.18<f<1.20; preferably, e=1.13, f=1.19.

Among them, the following conditions need to be met in the formulas of the above three modes: 0.8<s/S<1.2, 0.8< l/L<1.2.

4) The drying equipment starts drying operation.

As a preference, multiple sets of benchmark data are input in step 1);

Preferably, when there are two or more sets of benchmark data, the user can select the benchmark data through the user interface.

Preferably, the system can automatically select a reference data with the smallest value of ((1-s/S) ² +(1-l/L) ² ).

Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (6)

1. a drying unit for sheet material, comprises casing, arranges the thermal treatment zone and preheating zone in casing, preheating zone is arranged on the front portion of the thermal treatment zone and is connected with the thermal treatment zone, along conveyer belt direction of transfer, temperature t is set to the function of the distance x of distance thermal treatment zone entrance, t=f(x)

In the thermal treatment zone, f'(x) <0, f''(x) >0;

In preheating zone, f'(x) >0, f''(x) >0;

Wherein f'(x), f''(x) be f(x respectively) first order derivative and second derivative.

2. drying unit as claimed in claim 1, comprise heater block, temperature sensor, Programmable Logic Controller and conveyer belt, described conveyer belt is through casing, conveyer belt arranges speed control unit, speed control unit and Programmable Logic Controller carry out data cube computation, Programmable Logic Controller is according to the thickness of sheet material and moisture content, and Negotiation speed control assembly controls the speed of conveyer belt; Conveyer belt transfer control mode is as follows: in Programmable Logic Controller stored in reference data sheet metal thickness be L, quality moisture content is S, the temperature of heating is T, the transfer rate of conveyer belt to be V be sheet metal thickness be L, quality moisture content be S time, the absolute temperature of the heating needed is T, and the transfer rate of conveyer belt is V;

When the thickness of sheet material is for becoming l, quality moisture content is when becoming s, and the biography speed of conveyer belt meets following relation:

T keeps fiducial temperature T constant, and the transfer rate change of conveyer belt is as follows:

V/v=(s/S) ^c* (l/L) ^d, wherein c, d are parameter, 1.12<c<1.18,1.25<d<1.29;

The following condition of demand fulfillment in above-mentioned formula: 0.8<s/S<1.2,0.8< l/L<1.2;

In above-mentioned formula, temperature T, t are absolute temperature, and unit is K, and be the average heating-up temperature in casing, speed V, v unit is m/s, and sheet metal thickness L, l are centimetre that moisture content s, S are mass percent.

3. drying unit as claimed in claim 1, it is characterized in that, when adjusting temperature, the heating power of the heater block of all thermals treatment zone takes identical amplification or the range of decrease.

4. drying unit as claimed in claim 1, is characterized in that, when adjusting temperature, along with the direction of transfer of conveyer belt, the amplitude that the heating power of the heater block of the thermal treatment zone increases or reduces reduces gradually.

5. drying unit as claimed in claim 1, it is characterized in that, when adjusting temperature, the heating power of the heater block of all preheating zones takes identical amplification or the range of decrease.

6. drying unit as claimed in claim 1, is characterized in that, when adjusting temperature, along with the direction of transfer of conveyer belt, the amplitude that the heating power of the heater block of preheating zone increases or reduces raises gradually.