During operation, the circulating air is heated by the heat exchanger in the fresh air unit. The design drying temperature is 0 ~ 80 ± 5 ℃, and the heating energy is natural gas. The hot air is sent from the top and returned from the bottom. To ensure that the air volume and temperature of each section of the drying room are uniform. During the drying process of workpieces, the residual organic solvent in the paint film of workpieces is constantly volatilized. In order to make the content of organic solvent in the gas in the drying room lower than the lower limit of explosive concentration, the drying room keeps safe operation, a certain amount of fresh air shall be added to the circulating hot air, and a certain amount of high concentration exhaust gas shall be discharged. The drying room is equipped with a temperature sensor to display the temperature of each point and an automatic temperature regulating device to control the temperature fluctuation within ± 5 ℃.

When the natural gas heating paint drying room is in operation, the fresh air is heated by the burner, passes through the filter under the action of the circulating fan and enters the air supply pipe at the bottom of the drying room. The hot air is discharged from the air outlet and enters the drying room to dry the paint film on the surface of the workpiece. By using the principle of hot air rising, the return air pipe is set at the top and then enters the circulating air unit to make the hot air be recycled.

Main material of chamber

□ 120 is adopted for the column and beam of the drying channel framework × one hundred and twenty × 5 square pipe production, purlin adopts □ 50 × fifty × 4 rectangular steel pipes, all of which are subject to anti-corrosion treatment, have the characteristics of good thermal insulation performance and high support stiffness; The thickness of the inner wall plate is δ 1.5mm galvanized steel plate, the thickness of the outer wall plate is δ 0.80mm corrugated color steel plate with intermediate filling δ 200mm thick rock wool sandwich (rock wool density is 120kg / m3) insulation board, and the material of the chamber body is δ 1.5mm cold plate, strong thermal insulation performance, so that the temperature of the outer wall plate is not higher than 5 ° C of the room temperature.

Steel structure platform

It is welded with 14 # channel steel and laid on the table δ The 4mm pattern plate is designed above the drying room and directly connected to the ground through the column, that is, the natural gas heating paint drying room itself does not bear the steel structure platform, and the two are separated. The hot air circulating heating system is installed on the steel structure platform. In order to facilitate the maintenance of operators, a steel ladder is set on one side of the platform, and safety protection railings are set around. The ladder and railings are designed and manufactured according to national standards.

Electric liftgate

The international new type roller shutter door is selected, which has good thermal insulation and strong bending resistance to prevent condensate; The surface of the profile is multi-layer baking paint or film layer, which has excellent scratch resistance, corrosion resistance, non-corrosion, wear resistance, knock resistance and impact resistance; During startup and operation, it is fast and noiseless (the speed can reach about 0.1m/s and the noise is less than 58db)

In order to ensure the adhesion between the paint film and the workpiece substrate in winter, it is generally required that the ambient temperature should be ≥ 15 ゜ C. the added heating device ensures the spraying effect of the operation at low temperature in winter and is integrated into the air supply system; According to the requirements of heating power value in winter, btg28p two-stage fire gas burner of Italian "Baltur" company is selected as the burner, which is safe and energy-saving

SUS304 is adopted for the inner tank of heat exchanger; δ 4mm stainless steel is made by argon arc welding. The two process heat exchange design structure of the whole machine is reasonable, the heat exchange area is large, and the heat exchange efficiency is high. At the same time, it is equipped with an air pressure switch to effectively monitor the system operation. When there is no circulating air in the system, the burner is immediately cut off and the heating is stopped. So as to ensure the safe and reliable operation of the equipment

Channel steel, angle steel and industrial profiles are welded into a frame, and the four sides are covered δ 100mm rock wool color steel sandwich panel with access door.

The fan adopts double suction bkkf / bydw / b4-82 explosion-proof centrifugal fan with good performance, high efficiency, beautiful appearance, compact structure, stable operation and convenient installation; The frame is welded with channel steel and angle steel to ensure its bearing capacity; Air supply pipes are all made of δ 1.2mm high-quality galvanized steel plate is made of bite, and the pipeline is formed without deformation; A damping or elastic reducer is installed at the bottom of the fan, and a fan noise reduction room is set to ensure that the system noise is controlled below 75dBA

The air supply pipe and return pipe of the heating system guide the hot air to circulate in the drying room and transfer the heat to the workpiece. The outdoor part of the air pipe adopts δ 30mm rock wool thermal insulation material package, easy installation, beautiful appearance. In order to promote the strong circulation of hot air in the room and make it evenly distributed, regulating butterfly valves are set at the inlet of air supply pipe, return pipe, fresh air makeup pipe and exhaust gas discharge pipe. The air supply and return pipes in the drying room are all made of δ 1.5mm galvanized plate undercut fabrication without welding. The appearance of the pipeline is ensured. Flange connection is adopted for connection between pipelines, and asbestos rope is filled between flanges as sealing material.

A set of workpiece induction device is installed at the inlet of the oven. When the conventional workpiece passes through, the infrared radiation can turn on about 50% of the power to meet the temperature rise requirements. If there is an unconventional workpiece (i.e. the size is too small) and it is too far away from the radiation panel, the induction device can send a signal in advance. Before the workpiece reaches the designated station, the output power of the radiation panel is increased in advance, and the temperature of the surface paint is detected with the temperature resistant infrared thermometer in the oven, The output power of the panel can be automatically adjusted to ensure that the paint temperature on the surface of the workpiece is 80 ° C ± 5 ° C

A filter device is set at the air outlet to ensure the cleanliness of circulating air. 3001gg high-temperature resistant coarse effect flat filter is selected. It is made of alkali free glass fiber filaments. The fiber layer is thin to dense from the windward side to the leeward side, effectively blocking dust. It has the characteristics of large air volume, small resistance, flame retardancy, chemical corrosion resistance and excellent radiation resistance.

In order to reduce the energy loss during the system operation, an air curtain is set at the entrance and exit of workpieces to cut off the heat outflow by high-speed air flow.

The drying temperature is up to 200 ℃, which can be adjusted and set according to the needs to adapt to the development of coating production and the use of different coatings. The temperature in the furnace is displayed and automatically controlled by the digital temperature controller. One point is set at the front, middle and rear of the drying room. The middle point controls the temperature, and the front and rear two points display. A temperature display is set in the heating room. The collected signal is sent to the temperature controller of the control cabinet. The temperature controller automatically controls the work of the heater according to the set drying temperature value to ensure that the temperature in the room meets the completion of the drying task. It has the function of overtemperature audible and visual alarm and automatic interlock shutdown.

The heating system is equipped with an air pressure switch. When no air is detected, the control signal will be sent immediately to cut off the heater and stop the operation to avoid the occurrence of "dry burning".

Activated carbon adsorption + RCO catalytic combustion

The organic waste gas can be adsorbed by using the adsorption characteristics of activated carbon micropores, and the waste gas with low concentration, low temperature and hydrocarbon can be treated. The solvent can be recovered and reused, and the purification efficiency is as high as 90-95%. Activated carbon is a non-polar adsorbent with hydrophobic and organophilic properties. It can absorb most organic gases, such as benzene, aldehydes and ketones, alcohols, hydrocarbons, etc., as well as odor substances. After the adsorption is saturated, it can be desorbed and regenerated by hot air and put into use again

Molecular sieve zeolite runner adsorption + catalytic combustion

The zeolite runner concentration area can be divided into treatment area, regeneration area and cooling area. After collection and pretreatment, VOC organic waste gas enters the zeolite molecular sieve runner system. Through the continuous process of adsorption desorption concentration of zeolite molecular sieve runner, large air volume and low concentration organic waste gas is concentrated into small air volume and high concentration waste gas, and then enters the regenerative oxidation furnace for combustion purification, And effectively utilize the surplus heat released by the combustion of organic matter.

Safety alarm system

The differential pressure detection alarm adopts the sound and light alarm mode, and is interlocked with the air supply and exhaust system to cut off the fan operation and remind the operator to replace the filter material; Install a pressure lock on the pedestrian door for control. When the indoor pressure is too high, it can automatically open the pedestrian door for pressure relief; The combustible gas detection and alarm instrument has a central control system and multiple detection channels, which can connect multiple probes. The probes are placed on each indoor working section to monitor the indoor combustible gas concentration at any time and send out alarm signals.

Electronic control system

The electric control scheme of the natural gas heating paint drying room strives to be economical, applicable, reasonable in structure, safe and reliable. The principle of proximity setting is adopted. The electric control cabinet is vertical with front and rear doors. All electrical components are installed in the control cabinet. Each motor operation control circuit is equipped with corresponding low-voltage circuit breaker, thermal relay and other protection components to realize short-circuit and overload protection of the motor; Air supply and exhaust are automatically controlled by PLC; The user is responsible for the primary power distribution (i.e. power transmission from the workshop power distribution cabinet to the equipment electric control cabinet), and we are responsible for the secondary power distribution (i.e. power transmission from the equipment electric control cabinet to the equipment). The design and installation of the electric control system comply with the relevant national electrical safety specifications, with high reliability, reasonable layout and convenient maintenance.