Technical requirements of veneer dryer

The veneer dryer is a very important machine in the plywood production line. The main function is to remove excess water from the veneer and produce high-quality plywood. Therefore, choosing a high-quality veneer dryer is very important for plywood manufacturers. Today we first understand the technical requirements of the veneer dryer.

1. General technical requirements.

(1) The design, manufacture and acceptance of the veneer dryer should comply with the provisions of GB/T 18262 in addition to the provisions of this standard.

(2) The specifications, other parameters and structure of the veneer dryer should conform to the relevant provisions of this standard and design documents.

(3) The structure of the veneer dryer should have sufficient rigidity, and the thermal deformation generated during normal operation should not adversely affect the working accuracy.

(4) The outsourcing matching parts used in the veneer dryer should meet the current standard, and a certificate of conformity is required.

(5) The veneer dryer should be equipped with display devices such as internal temperature, relative humidity, heating system pressure (or temperature), veneer feed speed, etc. and fire extinguishing equipment.

(6) When the veneer dryer is running, each working mechanism should be clever, accurate, stable, coordinated and reliable, and no traffic jams when working.

(7) The dry running noise of the veneer dryer should not exceed 85 dB(A) at the end of the board.

(8) The air velocity of the spray box spray hole in the heating zone of the jet veneer dryer should not be less than 15 m/s.

(9) The thermal insulation devices such as the top plate, side plate and door of the veneer dryer should have good thermal insulation performance. When the temperature in the heating zone reaches 140C, the average temperature of the surface of each wall plate should not exceed 50C.

(10) The temperature difference in the heating zone of the veneer  dryer should meet the requirements of Appendix B.

(11) The electrical equipment of the veneer dryer should meet the relevant regulations of GB/T 5226 1.

2. Requirements for main parts of veneer dryer

(1) The steel parts before and after welding in the veneer dryer should be corrected. There should be no obvious hammering and other scars: the straightness of the straightened parts should not exceed 1000:1.0.

(2) The diagonal difference between the inner and outer frames of the rack should not exceed 3 mm after welding.

(3) The top panels, side panels and doors of the thermal insulation device should meet the following requirements:

    a. The following deviations should not be exceeded: length 1000: 1.0, diagonal 1 000 2.0; warpage 1000: 1.5;

    b. No obvious scars such as hammering on the surface;

    C. The insulation material of the veneer dryer must be dried first, and its spreading should be uniform and dense.

(4) The height deviation of each roller support plate of the veneer dryer should not be greater than 1mm; the deviation of the height position of the center of the lattice or flower plate hole used for the spray box of the device should not be greater than 1 mm.

(5) The manufacturing accuracy of the fan should meet the requirements of GB/T 13274 or GB/T 13275. The impeller of the fan must be subjected to dynamic balance experiments and corrections, and the precision of dynamic balance should not be lower than G 6.3.

(6) The spray box should meet the following requirements:

a) The welding surface should be flat and the axial straightness of the spray box surface should not be greater than 4 mm;

b) The mutual distance between the nozzle holes along the axis of the spray box should not be greater than 1 mm;

c) The connection between the nozzle and the box should be tight. No air leakage.

(7) The heat exchanger should meet the following requirements:

a) The deviation of the total number of heat sinks should not be greater than ±1%:

b) The pitch and parallelism error of the heat sink should not exceed ±15% of the specified pitch;

c) All welds should be smooth, smooth and firm, and must not leak.

(8) The quality of the trap should meet the relevant regulations of JB/T 9093.

(9) The pipeline of the dehumidifying device should be sealed, and the welding seam should be smooth, and no leakage is allowed; the butterfly valve in the pipeline should rotate smoothly, without any jamming.

(10) The equipment is assembled into a single assembly or large parts before leaving the factory, the inner wall of each insulation board and the spray box must be primed with heat-resistant paint, and the surface should be coated with heat-resistant silver powder paint; Outside the surface, the rest should be coated with heat-resistant silver powder paint; paint compatibility should be appropriate to prevent chemical reactions.

3. Assembly technical requirements

(1) The installation accuracy of the dryer rack should meet the requirements of Appendix C.

(2) The connection between each thermal insulation top plate, side plate, door and frame, spray box and frame and flower plate, each deflector and frame, and the connection of various air ducts must be firm and reliable. No air leakage.

(3) After assembling the pipes, valves, heat exchangers, etc. of the heating system, a pressure test shall be carried out. The pressure shall be tested at 1.25 times the maximum working pressure without leakage.

(4) The installation of the fan frame on the rack must be firm and reliable.

    The quality of the equipment directly affects the production efficiency. Knowing the technical requirements of the veneer dryer, I believe you have more understanding of the veneer drying opportunities.