NB/T 10420-2020Technical code for tobacco leaf curing in air-source heat pump flue-curing barns (English PDF)

3.1 Curing

The process of using natural temperature and humidity or artificial control of temperature and humidity to make the harvested tobacco leaves yellow, fragrant and dry. Including roasting, Drying, drying, etc.

3.2 Mature

Tobacco leaves have completed most of the growth and transformation process and have more identifiable maturity characteristics.

3.3 Optimum maturity

Suitable ripe.

Tobacco leaves have completed the process of growth and transformation and have obvious recognizable maturity characteristics.

3.4 Overmature

The growth and development of tobacco leaves exceed the requirements of maturity, and the dry matter is converted and consumed too much.

3.5 Leaf change

The yellowing degree and dry form changes of the tobacco leaves during the conditioning process are usually adjusted based on the changes in the high-temperature layer of tobacco leaves.

3.6 Yellowing degree

The sensory reflection of the overall state of the yellowing of tobacco leaves is expressed by the ratio of the area of the tobacco leaves turning yellow to the total area ("it is almost yellow").

3.7 High temperature layer

The part of the space where the air temperature is relatively high in the smoking room, that is, the bottom floor of the ascending airflow barn and the top floor of the descending airflow barn.

3.8 Low temperature layer

The part of the space where the air temperature is relatively low in the smoking room, that is, the middle smoke layer and the top floor of the airflow type roasting barn, and the middle smoke of the airflow type barbecuing barn. Layer and bottom layer.

4.1 Tobacco leaf maturity characteristics

4.1.1 The basic color of the lower tobacco leaves is green, with a slight yellowish appearance, some of the hairs fall off, the picking sound is crisp, the section is neat, and there is no stem. skin. 55 to 65 days after transplanting flue-cured tobacco.

4.1.2 The basic color of the central tobacco leaves is yellow-green, with more than 2/3 of the leaf surface falling yellow, the main veins are white, the branch veins about 1/2 are white, and the tip and edge of the leaf are present.

Yellow, with yellow mature spots on the leaf surface, and the angle of stems and leaves increases. 65 to 90 days after transplanting flue-cured tobacco.

4.1.3 The basic color of the upper tobacco leaf is light yellow, the leaf surface is fully yellowish, wrinkled, mature spots are obvious, the tip of the leaf is drooping, the edge of the leaf is wrinkled, the stem and leaf The angle is significantly increased. 90 to 110 days after transplanting flue-cured tobacco.

4.2 Principles of Tobacco Leaf Harvesting

4.2.1 The lower tobacco leaves are harvested early in time, the middle tobacco leaves are harvested mature, and the upper leaves are harvested fully mature.

4.2.2 Tobacco leaf harvesting should be carried out in the morning or morning, picking 2 to 3 pieces per plant each time. Upper tobacco leaves, 4 to 6 pieces, concentrated and mature, One-time harvest. Each tobacco leaf is harvested 6 to 8 times.

4.2.3 Tobacco leaves should be harvested immediately after the rain stops after a short period of time after they mature. When the long-term rainfall causes the tobacco leaves to turn green, wait until the tobacco leaves are re-greened. This time shows mature characteristics of harvesting.

4.2.4 Tobacco leaves of the same variety, part and maturity should be harvested each time.

4.3 Methods of harvesting tobacco leaves

4.3.1 All tobacco pickers first unify the tobacco leaf maturity standards, and then enter the tobacco rows to prepare to harvest mature tobacco leaves on both sides.

4.3.2 When the tobacco leaves are harvested, they should not be green or overripe, and the maturity and uniformity of the tobacco leaves should be consistent.

4.3.3 For a tobacco plant, first determine the tobacco leaf to be picked, and then hold the base of the stem end of the tobacco leaf with the middle finger and index finger, and place the thumb on the stem end Face, twisting to both sides, with the dull "dang" cracking sound at the base of the tobacco leaf, the tobacco leaf is picked off, and the stem of the tobacco leaf is "horseshoe-shaped".

4.3.4 When harvesting, you can pick tobacco with one hand and hold the tobacco leaves with the other. Approximately 20 to 30 pieces are in a bundle, and the tip of each tobacco leaf should be stacked on top of each other.

The base of the base is neat and consistent, placed between the rows of cigarettes or on the moist.

4.4 Stacking of tobacco leaves after harvest

4.4.1 After picking a certain area, take out the tobacco leaves, neatly put them in the car or basket, and transport them to the smoking room or other suitable smoking yard Therefore, it is placed so that the base of the tobacco leaf is on one side, and the tip of the tobacco leaf faces the other side of the rectangular tobacco leaf pile.

4.4.2 The entire operation process should be neat and consistent, handle with care. No exposure to sunlight, no squeezing, no damage to the quality of fresh tobacco leaves.

5.1 Classification of Fresh Tobacco

Before editing (clamping) tobacco, first classify the tobacco leaves according to the maturity difference, leaf size, and diseased leaves of the first maturity, moderate maturity and over maturity tobacco.

5.2 Classification (clip) cigarettes

On the basis of the classification of fresh tobacco leaves, the tobacco is compiled (clamped) separately, with the same rod and the same quality.

5.3 Method of making cigarettes

The leaf bases are aligned, the leaf backs lean against each other, the braiding is firm, and the distance between the bundles is uniform.

6.1 Classification of cigarettes

6.1.1 The same barn should be filled with tobacco leaves of the same variety, cultivation and management conditions, positions, harvest time, and maturity.

6.1.2 For the air-rising barn, fresh tobacco leaves that turn yellow quickly and have a slightly higher maturity are installed on the bottom layer; fresh tobacco leaves that turn yellow slowly and have a slightly poorer maturity Installed in the middle tobacco layer; fresh tobacco leaves with normal maturity are installed in the upper layer and other remaining spaces.

6.1.3 For the airflow down-curing barn, fresh tobacco leaves that turn yellow quickly and have a slightly higher maturity are installed on the top layer; fresh tobacco leaves that turn yellow slowly and have a slightly poorer maturity Installed in the middle tobacco layer; fresh tobacco leaves with normal maturity are installed in the bottom layer and other remaining spaces.

6.2 Packing distance

The barn should be filled with cigarettes without leaving any gaps. The distance between tobacco rods is 80 mm~100 mm; the distance between cigarette holders is 50mm~70mm.

7.1 Basic requirements

Tobacco leaves harvested on the same day should be prepared (clamped) cigarettes and filled with cigarettes, and the machine should be turned on for preparation. The technical requirements of the air source heat pump flue-curing room should meet The provisions of Chapter 4 in NB/T 10419-2020.

7.2 Location of temperature and humidity measuring points

7.2.1 The temperature and humidity sensor probes of the high temperature layer of the air-lifting barn or the low-temperature layer of the air-flowing barn are hung on the bottom of the barn.

The vertical distance above the tip plane (80-100) mm, and the middle position from the air outlet (1.8-2.0) m.

7.2.2 The temperature and humidity sensor probe of the low-temperature layer of the air-lifting barn or the high-temperature layer of the air-flowing barn is hung on the top tobacco leaf of the barn The vertical distance above the tip plane (80-100) mm, and the middle position from the air outlet (1.8-2.0) m.

7.3 Regulation process

7.3.1 Low temperature humidity control turns yellow

At the beginning of the preparation, in the early stage of yellowing, at an average heating rate of 2°C/h, from the natural temperature, within (8~10)h, the dry bulb temperature of the high temperature layer After the temperature rises to the requirements specified in Table 1, adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 1. Maintain this temperature and humidity for modulation, and the modulation time is as per Table 1 requires that until the tobacco leaf change target reaches the requirements of Table 1.

In the late yellowing stage, with an average temperature rise rate of 1°C/h, from the temperature and humidity conditions at the end of the yellowing stage, within (1~3)h, the high temperature layer After the dry bulb temperature rises to the requirements specified in Table 1, adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 1. Maintain this temperature and humidity to modulate, modulate The time is according to the requirements of Table 1, and the tobacco leaf change target reaches the stipulation of Table 1.

7.3.2 Stabilizing temperature, removing moisture and withering

In the early stage of withering, with an average heating rate of 1°C/h, within (2~4) hours, the condition of the high temperature layer dry bulb temperature from the end of the yellowing stage Raise to the dry bulb temperature specified in Table 2, and adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 2. Maintain this temperature and humidity for modulation, and the modulation time is as per Table 2 requires that when the tobacco leaf change target reaches the requirements of Table 2.

In the later stage of withering, with an average heating rate of 1°C/h, within (4~5) hours, the dry bulb temperature of the high-temperature layer was changed from the state at the end of the early stage of withering Raise to the dry bulb temperature specified in Table 2, and adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 2. Maintain this temperature and humidity for modulation, and the modulation time is as per Table 2 requires that when the tobacco leaf change target reaches the requirements of Table 2.

7.3.3 Ventilation dehydration fixation

In the early stage of color fixation, with an average heating rate of 1°C/h, within (2~4) hours, the condition of the dry bulb temperature of the high temperature layer from the end of the late stage of withering Raise to the dry bulb temperature specified in Table 3, and adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 3. Maintain this temperature and humidity for modulation, and the modulation time is as per Table 3 requires that until the tobacco leaf change target reaches the stipulation in Table 3.

In the late stage of color fixation, with an average heating rate of 1°C/h, within (2~3)h, the condition of the dry bulb temperature of the high-temperature layer from the end of the previous stage of color fixation Raise to the dry bulb temperature specified in Table 3, and adjust the wet bulb temperature of the high temperature layer to meet the requirements of Table 3. Maintain this temperature and humidity for modulation, and the modulation time is as per Table 3 requires that until the tobacco leaf change target reaches the stipulation in Table 3.

7.3.4 Temperature control, wet and dry tendons