SU960341A2 - Head box of paper-making machine - Google Patents

Description

The invention relates to papermaking machines, namely, nior boxers for putting weight on the grid of paper and board making machines, is an improvement of the known device. According to the main author. St. No. 720089 is known for the pressure head of the papermaking machine, which contains the collector body and the overflow ruler installed in it, which separates the body from the internal cavity, the overflow pocket, the downpipe above the overflow pocket, and the outlet tubes evenly mounted along it, the ends of which are lowered into overflow pocket. The upper air-rich suspension layers and foam pass inside the box above the overflow line into the overflow pocket. Since the pressure in the inner cavity of the box is above atmospheric, the suspension is squeezed out of the pocket through the discharge tubes into the drain pipe and is removed outside the head box. Outlet tubes provide a uniform and quick drainage of contaminated suspension 1. In a overflow pocket, this level of suspension must always be maintained; wherein the ends of the branch tubes remain immersed in the slurry. When the level drops below the allowable through the branch pipes, the air is blown under the pressure inside the box, which will lead to a sharp decrease in pressure and a violation of the mode of inlet of the suspension onto the grid of the paper machine. In practice, during operation of the headbox, due to the lack of stability of the supply system, there is a fluctuation of the level of the suspension inside the box, including in the overflow pocket. The purpose of the invention is to increase the reliability of the machine. This goal is achieved by the fact that one of the discharge tubes of the headbox of the paper machine is shortened relative to the others and has a sleeve which is telescopically connected to it, while the lower end of the sleeve may have a bevel. FIG. 1 shows a pressure box, a longitudinal section; in fig. 2 is a cross section A-A in FIG. one; in fig. 3 - node I in FIG. 2. The discharge valve contains a collector 1, a perforated plate 2, a housing 3 (the end walls of which are blind),

with perforated shafts 4 installed in the inner polorta and a pouring line 5 with an overflow threshold of 6, forming a overflow, pocket

A drain pipe 8 is installed above the overflow pocket with discharge tubes 9 installed along it with a uniform pitch, the ends of which are lowered into the overflow pocket.

The drain pipe has one shortened (relative to the others) outlet tube 10, at the free end of which is telescopically fixed, movable sleeve 11. The free end of the sleeve may have a bevel 12. The drain pipe has a valve 13.

The operation of the headbox is as follows.

The suspension flowing through the collector 1 passes through the perforated plate 2, evenly distributed across the width of the headbox, is stabilized by the perforated shafts 4 and through the narrowing channel formed by the bottom of the body 3 and the overflow line 5, goes to the grid of the machine. Above the suspension mirror is pressurized air (air cushion), which ensures the proper speed of the suspension out of the box.

The upper, air-rich layers of the suspension and foam pass over the overflow threshold b of the overflow line 5 into the overflow pocket 7. Since the pressure in the internal cavity of the box is above atmospheric, the suspension from the pocket 7 is squeezed out

tube 9 into the drain pipe, 8 and is removed outside the pressure box.

In this way, pals are removed.

The sleeve 11 is mounted on the shortened discharge tube 10 in such a way that its free end touches the suspension. With the submerged end of the sleeve, the suspension is removed through it, with the non-submerged end air is removed.

The principle of maintaining a constant level is based on the interaction between the level of the suspension and the air flow through the orifice of the sleeve 11. For example, as the level in the pressure box increases, the mass flow through the overflow line 5 increases. The level in the overflow pocket 7 increases and the end of the sleeve is immersed in the suspension. The flow of air through the sleeve is stopped, thereby causing an increase in air pressure in the pressure box. Under the action of increased pressure, the rate of mass outflow from the headbox onto the grid of the paper machine is increased, which, in turn, leads to a decrease and restoration of the initial level in the box and in the overflow pocket.

When the level decreases, reverse processes occur.

A slant 12 at the end of the sleeve allows the level to be more smoothly adjusted, which is set so that the slurry partially overlaps the opening. Through the non-submerged area, the air is continuously supplied to the discharge tube 10 and is removed through the drain pipe outside the headbox.

The valve 13 regulates the amount of discharge of the suspension, balances the pressure of the air cushion.

In this way, a reliable removal of the suspension that has passed over the overflow threshold is ensured and the possibility of air breakthrough from the headbox is eliminated due to the lower level in the overflow pocket.

Claims (2)

Invention Formula 1, Headbox boom of an agribusiness machine according to ed. St. No. 720089, characterized in that, in order to increase the reliability of the machine, one of the branch pipes is shortened relative to the others and has a sleeve which is telescopically connected to it. 2. The box according to claim 1, characterized in that the lower end of the sleeve has a bevel. . sources of information taken into account in the examination 1. USSR author's certificate No. 720089, cl. D 21 F 1/02, 1978. Suspension level AND. /