To play the paper machine, you must first get the headbox

To play the paper machine, you must first get the headbox

The headbox has always been considered the heart of the paper machine and plays a decisive role in the quality of the paper. The headbox of a modern paper machine is very automated, but it is still necessary to know how it operates. This article mainly introduces the use, operation and maintenance process of the headbox.

Before the headbox is turned on, the following should be done:

1) Whether there is water in the short circulation system tank;

2) Whether the sealing water of the slurry pump and the pressure screen is turned on;

3) Whether the headbox cleaning spray pipe is turned on;

4) All cleaning holes and inspection holes are closed;

5) Whether the upper lip is in its normal operating position;

6) Whether the lubricating spray pipe is open;

7) Whether the thermal compensation system is turned on.

The sizing pump can only be turned on when the following conditions are met:

1) The short circulation system has been operated;

2) The dilution water circulation system is running and the pressure has been stabilized;

3) The forming part has started to run.

The headbox control system can be interlocked through relevant conditions to realize the following automatic functions:

1) When the dilution water pump is turned on, the return valve of the dilution water main pipe will automatically open to the set position, and when the water pump is turned off, the valve will be automatically closed;

2) When the sizing pump is turned on, the return valve of the headbox feeding main pipe will automatically open to the position in the previous operation, and when the sizing pump is turned off, the valve will automatically close;

3) If the sizing pump suddenly stops, the headbox pressure control will automatically switch from automatic control to manual control; if the forming part suddenly stops, the sizing pump and dilution pump will automatically stop;

4) The control and adjustment of the water level of the headbox and the operation of the backflow can be performed automatically or manually, and the adjustment of the dilution water pressure can also be performed automatically or manually;

5) If the dilution pump suddenly stops, the sizing pump will automatically stop.

The boot sequence is:

1) Open the forming part and check whether the lubricating spray pipe of the ceramic panel is open, and check the speed of the forming part;

2) Turn on the vacuum system of the forming part;

3) Turn on the dilution circulation system;

4) Turn on the short circulation system;

5) According to the running speed of the paper machine, adjust the pressure head and liquid level of the headbox to the set value, and enter the automatic control state;

6) Open the pressure screen;

7) Turn on the sizing pump;

8) Check the headbox pressure;

9) Turn on the slurry pump.

Before the stock pump is turned on, the head box pressure should be adapted to the running speed of the paper machine. If the pressure is low, the stock will plug the head box.

The precondition for shutdown is that the vacuum suction roll has been raised to the high position and the spray pipe for washing the wet web is open. The short circulation system is flushed with water throughout the process to keep the headbox clean. Rinse the slurry pipeline after the white water tank outside the machine to prevent the pressure screen from being blocked after shutdown.