Structure description and performance characteristics of Air-cushioned Headbox

One, structure description and performance characteristics

The Air-cushioned Headbox is composed of a square cone tube device, a homogenization roller device, an upper lip plate adjustment device, a box, a control system, a spray device, an air circuit system and other parts. The headbox is specially designed according to the working condition parameters provided by the user to ensure the working performance.

1. Square cone pipe device

1). The square cone pipe adopts one-way main pipe for slurry feeding, and three-step orifice plate for slurry distribution. The square cone tube is composed of a large square tube, a square cone tube, and a small square tube. The square cone pipe is equipped with a pressure balance pipe, and the square cone pipe section can be turned down and cleaned easily;

2).The material of the step orifice plate is plexiglass;

3). The square cone tube is made of stainless steel (304). Both the large square tube and the small square tube have matching flanges.

2. Homogenizing roller device

1) The homogenization roller device is composed of a lip homogenization roller and a throat homogenization roller;

2). Homogenizing roller diameter Φ219, opening rate throat homogenizing 41%, lip homogenizing roller 46%;

3). The homogenization roll is made of customized high-quality cold-rolled stainless steel tube (304), double helix arrangement;

4). The homogenization roller is driven by a 100-thread pinwheel reducer, and the user-provided frequency converter can be steplessly changed between 9-50 rpm according to the process requirements.

3. Upper lip plate adjustment device

The upper lip board adjustment device is composed of upper and lower lip boards, beams, coarse and fine adjustment mechanisms, and large and small rotating shafts.

1) The upper lip plate adopts a single joint adjustment mechanism;

2). The shotcrete adopts a combined lip, with a horizontally straight and well-elastic vertical small lip to further improve the slurry distribution. The vertical small lip board is equipped with small spacing (approximately 115mm) for precise fine-tuning, and the dial indicator shows a value of 0.01mm, which can be precisely adjusted;

3) The opening adjustment of the upper lip plate adopts a worm gear structure;

4). The lower lip plate is made of high-quality stainless steel (316L), and there is no screw hole in the box; the vertical small lip plate is made of high-quality stainless steel (316L);

5). There are gill flow holes on both sides of the lip to adjust the weight of both sides of the paper web. The gill flow holes have matching flanges.

4. Cabinet

1). The base of the headbox adopts Q235A, and the mirror panel is covered;

2). The front and back wall panels and the wall panels on both sides of the box body are all made of stainless steel plate (304);

3). The operating side wall panel is equipped with a sight glass to observe the slurry flow state;

4). The box body is equipped with front and back walking platforms and escalators, all made of stainless steel;

5). There is a low-voltage light on the top of the box cover;

6). The rear wall panel is equipped with a manhole device;

7). The box is equipped with a front wall overflow, the overflow hole has a matching flange and a pipe;

8). The parts in contact with the slurry in the box body are all finely polished to ensure that there is no wire hanging and no slurry hanging. The outer surface is clean and tidy;

9). The lip part and the back section of the step orifice are equipped with cleaning holes to facilitate the cleaning of the headbox.

5. Spray device

6. The headbox is equipped with a spray device with a rotating proprietary nozzle, and a filter at the entrance of the spray device (provided by the user)

7. Pneumatic system (provided by the user)

1) The air-cushioned pressure of the Air-cushioned Headbox is directly supplied by the air system, and its equipment includes low-pulsation Roots blowers, inlet and outlet silencers, racks, motors, valves and pipes.

2). The blower adopts frequency conversion speed regulation and is controlled by the control system.

8. Control system (user-supplied)

The control of the Air-cushioned Headbox includes the control of the slurry level and air cushion pressure in the box. The slurry level is obtained by the liquid level sensor and transmitted to the computer. The total pressure head is the sum of the slurry level and the air cushion pressure, and the signal is obtained by the pressure sensor through the slurry level. The decoupler (software) of the total pressure signal, after processing, transmits the execution signal to the frequency converter of the sizing pump and the blower motor to automatically control the sizing device and the spraying pressure required by the headbox. The control accuracy of slurry level and total pressure are both ±0.5%.