US3468756A - Paper machine head box support - Google Patents

Description

Sept. 23, 1969 T. VILLA 3468,756

PAPER MACHINE HEAD BOX SUPPORT Filed March 28, 1966 '2 Sheets-Sheet 1 FIG 1 Imam-org; 7': Villa w giv- ATTORNEBS Sept. 23, 1969 1mm" 3468,756

PAPER MACHINE HEAD BOX SUPPORT I Filed March 28, 1966 2 Sheets-Sheet 2 FIG 3 FIG 4 i i i i i [III/Ill] V 1 ,4 7' 5 J E /l/l/l/l/l/l/ /////1/////r LLlj/l/l/ll/ IILLL/[j/l/Ll/ 1/ /1///// 11/777777777777/ lT/1L1/1/l/ll/777Z77T7277777 INVENTOIL: I

T Villa.

United States Patent US. Cl. 162344 4 Claims ABSTRACT OF THE DISCLOSURE A support for a paper machine head has a box beam the top side of which carries the lower lip of the machine cutter, the beam being provided with means, such as a channel or channels for a heating medium, producing temperature dilferences in the beam as the result of which the top surface of the beam and the lower lip are maintained in a straight and horizontal position.

This invention relates to a method and device for compensating the deflection of the lower lip in the head box cutter of a paper machine. Within the head box prevails a pressure which tends to cause deflection of the structional parts of this box. As the operating speed and breadth of paper machines ever increases the pressure within the head box becomes so great that the same will cause harmful deflection of the lower lip of the head box cutter specifically. Hence, the downward deflection of the lower lip of the head box cutter must be compensated for. The supporting beam under the lower lip has heretofore been supported only at both ends thereof to the frame of the machine. Insofar as this beam is supported from three points, huge additional forces would be formed to load the frame and the harmful deflection of the lower lip would still not be adequately compensated for.

The object of this invention is to eliminate the downward deflection of the lower lip in the head box cutter of a paper machine. A characteristic feature of the method according to the invention is that the top part of the supporting beam under the lower lip in a head box cutter is heated and/or the bottom part of the same beam is cooled. When the top side of the supporting beam is warmer than its bottom side it will follow that the supporting beam and the lower lip will curve upwards on account of different thermal expansions. Hence, the supporting beam will tend to bend itself in the direction opposite to that that the pressure exerted upon the supporting beam by the head box tends to deflect the same. When the temperature difference between the top and bottom sides of the supporting beam has a certain value the deflection in the supporting beam and the thereto adjoining lower lip, caused by the pressure in the head box is compensated for in full. Because the deflection caused by the head box pressure in the supporting beam can be determined in advance the temperature difference between the top and the bottom sides of the supporting beam causing the total compensation of the deflection by the head box pressure can be calculated. The temperatures of the top and the bottom sides of the supporting beam can be measured continuously and the supporting beam can be provided with automatic controls with which a certain predetermined temperature difference can be maintained. Heating of the top side of the supporting beam can be done by any suitable means as for instance fluid, gas or steam or electricity. Cooling the bottom side of the supporting beam can be done with any suitable means as for instance with fluid or gas. If, for some reason or another it is not desired to totally compensate the deflection of the supporting beam or if it is desired Ice to deflect the same upwards from the middle this can, of course, be achieved by making the temperature difference between the top and the bottom sides of the supporting beam smaller or greater than that difference needed for compensating in full the said deflection.

Hereinafter will be described the device, the supporting beam, used in the method according to this invention with reference to the embodiments shown in the accompanying drawings.

In the drawings, FIGURE 1 is an end view of the head box of a paper machine, sectioned to show the supporting beam. FIGURE 2 illustrates the supporting beam shown in FIGURE 1 as sectioned along line H-II of FIGURE 1. FIGURE 3 is a vertical sectional view along the length of a supporting beam according to another embodiment of the invention. FIGURE 4 shows a vertical sectional view along the length of a supporting beam according to a third embodiment. FIGURE 5 shows a fourth embodiment of the supporting beam also in vertical sectional view.

In all the embodiments the head box supporting beam 1 carries on its top side the lower lip 2 of the cutter and has its two ends supported on the machine frame 3. The supporting beam is hollow and is rectangular in crosssection. v

In the embodiment shown in FIGURES 1 and 2, upon the top surface of the supporting beam is a channel 4 extending from end to end and of width equal to the hollow within the beam. Through this channel flows warm fluid, gas or liquid, so that the upper side of the supporting beam is heated. The bottom side of the supporting beam has a channel 5 similar to the one on the top surface and through this channel flows fluid liquid or gas, for cooling the said bottom side. By selecting the temperatures of the upper and lower sides of the supporting beam so that the temperature difference eflects upward deflection of the supporting beam, the downward bending distortion of the supporting beam due to head box pressure may be compensated in full or to any desired degree.

The supporting beam shown in FIGURE 3 differs from the hereinabove described only in that only the bottom side of the supporting beam 1 is provided with a channel 5 similar to the one upon the aforedescribed supporting beam 1. Through this channel 5 flows fluid, liquid or gas, for cooling the bottom side of the supporting beam. The temperature of the top side of the supporting beam is not changed in this embodiment.

The supporting beam 1 shown in FIGURE 4 lacks channels, both on its top side and on its bottom side. In this case the bottom side of the supporting beam is cooled by means of a jet pipe 5 under the bottom side.

The supporting beam shown in FIGURE 5 carries upon its top side a channel 4 similar to the one on the supporting beam shown in FIGURES 1 and 2 but lacks a channel on its bottom side. Warm fluid medium, liquid or gas, flows through channel 4 for heating the top side of the supporting beam.

The invention is not to be limited only to the hereinabove described embodiments for the same can be modified within the scope of the invention, because the main principle is solely that the top side of the supporting beam is kept warmer than the bottom side.

I claim:

1. In combination with a paper machine head having a cutter with a lower lip for the flowing pulp stock, and a foundation; a support consisting of an elongated box beam having a bottom portion supported at two ends by said foundation and a top portion supporting said lower lip, said box beam comprising at least one channel for a flowing heat exchanging medium to maintain a temperature difference between said top and bottom portions and thereby counteracting pressure exerted upon the lower lip by the head and maintaining said top portion and said lower lip straight and horizontal during operation.

2. A support in accordance with claim 1, wherein said channel is located in said top portion and extends between the two ends of the box beam.

3. A support in accordance with claim 1, wherein said channel is located in said bottom portion and extends between the two ends of the box beam.

4. A support in accordance with claim 1, having a channel located in said top portion and another channel located in said bottom portion, each of said two channels extending between the two ends of the box beam.

References Cited FRANK T. YOST, Primary Examiner U.S. Cl. X.R.

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