The energy-saving and environmentally friendly air-energy heat pump heat source drying kiln consists of an air-energy heat pump, an aluminum alloy (brick-concrete structure) kiln body, a kiln door (lifting door device), a heating system, a humidity control system, an air circulation system, an air intake and exhaust system, an electric auxiliary system, a detection system and a control system.

1. Heat source

The heat source part of the energy-saving and environmentally friendly air-energy heat pump heat source drying equipment is an air-energy heat pump dryer. The heat pump main unit compresses and collects the heat in the air to produce high-temperature hot air of 70-75℃, with an energy-saving efficiency of 3.5 (1KW of electricity compresses the heat in the air to produce 3.5 times the heating capacity, about 3000 kcal);

The air energy heat pump is an energy-saving and environmentally friendly product advocated by the country. It has no exhaust gas and pollution. It is a new heat source configuration for wood drying equipment. It is particularly suitable for use in areas with an average climate temperature of more than 20℃. It is also suitable for areas with high environmental protection requirements and customers who focus on energy saving needs.

2. Kiln body

In addition to meeting general building requirements such as durability, the kiln body of the drying kiln must also meet special requirements such as insulation, sealing and corrosion resistance. There are two types of kiln bodies: civil kiln body and metal kiln body. The civil kiln body is designed according to special requirements; the inner and outer layers of the metal kiln body are aluminum alloy plates, with a flame-retardant polyester insulation layer in the middle, and the kiln body frame is an aluminum alloy profile. Both the civil kiln body and the aluminum alloy kiln body are well sealed, have sufficient insulation performance, and can effectively resist corrosion. The ceiling in the kiln is made of aluminum plates or concrete.

3. Kiln door

Kiln doors are available in three types: single-leaf door, double-leaf door and hanging door. When two or more connected kilns are built, the kiln door is usually a hanging door, and a door lifter is required when a hanging door is used. The structure of the kiln door is the same as that of the aluminum alloy kiln body, which is heat-insulating and anti-corrosive. To ensure the sealing of the kiln door, a special silicone sealing ring with high temperature resistance, anti-aging and good elasticity is inlaid around the kiln door to ensure that the kiln door does not leak. The door lifter adopts a hand-cranked worm gear structure, which can be suspended or floor-standing, easy and flexible to operate, and stable and reliable in action.

4. Heating system

The main body of the heating system is the heater. The quality of the heater is not only related to the life of the heater, but also to the heat transfer efficiency of the heater. The heater used in most drying equipment is a new type of steel (stainless steel or seamless steel) aluminum composite integrally rolled fin tube heater, with no wrinkles on the fins, small air flow resistance, high heat transfer efficiency, good corrosion resistance and long service life.

5. Humidity control system

Although the humidity control system is simple, it is very important to ensure the quality of wood drying. The steam spraying pipe of the humidity control system is made of stainless steel pipe (or aluminum alloy pipe), thus avoiding the disadvantage of corrosion and reduced service life caused by carbon steel pipe. When steam heating is used, normal pressure saturated steam is sprayed into the kiln; when high temperature water heating is used, saturated steam or atomized water is sprayed into the kiln.

6. Air circulation system

Air circulation is an important means to speed up drying and ensure uniform drying. In order to improve the sealing of the kiln and the reliability of the fan operation, a high-temperature resistant and moisture-proof motor can be installed in the kiln together with the fan for direct transmission. The fan is specially designed to be the most advanced high-efficiency energy-saving precision die-cast aluminum alloy fan axial flow fan with symmetrical arrangement of wing-shaped twisted blades. It has large air volume, high air pressure, low energy consumption and long service life.

7. Intake and exhaust system

The intake and exhaust device can be automatically controlled or manually controlled. The dehumidification motor (torque) of the automatic control system is convenient and practical, and can realize multi-level control. Whether it is automatic control or manual control, the operation is very convenient and the action is very flexible.

8. Detection system

The detection system mainly refers to the detection of wood moisture content and the detection of medium temperature and humidity. The moisture content of wood is detected by electrical measurement, which can simultaneously measure the moisture content of 4-8 measuring points in the kiln. It is convenient and fast to use, with digital display, accurate and reliable readings.

The temperature difference method is used to detect the humidity of the medium, and the device used is a dry-bulb thermometer. This dry-bulb thermometer consists of two temperature sensors with the same accuracy. The temperature-sensing part of one of the thermometers is wrapped with a gauze sleeve, and the end of the gauze sleeve is immersed in a water tank. This thermometer is called a wet-bulb thermometer. Since the evaporation of water requires heat, the reading of the wet-bulb thermometer is lower than that of the other adjacent thermometer, the dry-bulb thermometer. The lower the reading of the wet-bulb thermometer, the drier the medium. The principle is: when the medium in the kiln is relatively dry, the faster the moisture on the wet-bulb gauze sleeve evaporates, and since evaporation requires heat consumption, the lower the reading of the wet-bulb thermometer, thereby determining the humidity of the medium.

9. Control system

The wood drying process is essentially a process of heat and moisture exchange between the drying medium and the wood. Therefore, the control of the wood drying process is actually the control of the medium conditions. The medium conditions closely related to wood drying are mainly temperature, humidity and circulation speed. The circulation speed is determined by the fan. Once the fan is turned on, it will continue to run and is generally not controlled. Therefore, the actual need may be to control only the temperature and humidity of the medium.

10. Electric auxiliary system

The energy-saving air energy heat pump heat source is affected by the heating capacity because the heating speed is affected by the heating capacity. When the heating time is required, the heating time affects the entire drying time. Therefore, electric heating is configured to assist the heating to make the whole set of drying equipment perfect. The electric heating rack is made of anti-corrosion stainless steel material, with fast heating speed, safety and reliability.