The way of pulp feeding in headbox

The way of pulp feeding in the headbox

The role of the headbox:

1. The headbox is the heart of the paper machine;

2. Turn the pulp flow in the tube into a thin and uniform pulp flow covering the full width of the paper machine; 3. The fibers are in a suspended state without agglomeration or pulp flow (streaks) direction.

Slurry feeding method of headbox:

1. Feed pulp from the high-level box to the headbox (commonly used at medium and low speeds)

a. Circular pulp screen - pulp collecting box - pulp pump - high-level box;

b. Rotor screen - high level box - headbox

2. Use a pump to supply pulp to the headbox (for high-speed paper machines, the pulp supply speed is required to be fast): rotor screen - stabilizer box - pulp pump - headbox

Slurry preparation: prepare the raw material pulp whose concentration has been controlled, the pulping after the thinning and dilution of the dry and wet broken paper of the paper machine, and various auxiliary materials such as fillers, pigments, and sizing materials added according to the needs of the product, according to the proportion required by the process. Hybrid operating unit. The pulp mixing device is a device that controls the flow of various materials to adjust and measure.

Dilution of pulp: In the pulping pool before the paper machine, the concentration of pulp is usually about 3%, and the concentration of pulp in the headbox should be more than 1%. One of the basic operations is to dilute the pulp with the white water released from the wire section of the paper machine before the pulp is transported to the headbox, in order to select the pulp and facilitate the formation of the pulp on the wire. This operation of diluting pulp is generally referred to as flushing.

The dilution method can be roughly divided into mixed box type (mostly used for rotary wire paper machines and low-speed narrow-width Fourdrinier paper machines) and punching tank type.