US1980481A - Acidproof beater bar - Google Patents

Description

Nov. 13, 1934. F. M. GLOYD ACIDPROOF BEATER BAR Filed June 25; 1931 INVENTOR,

A TTOR/VEKS'.

Patented Nov. 13, 1934 UNITED STATES ACIDPROOF BEATER BAR Frank M.

Gloyd, Dayton,

Ohio, assignor to Simonds Worden White Company, Dayton, Ohio, a corporation of Ohio Application June 23, 1931, Serial No. 546,218

1 Claim. (01. 92-22) This invention relates to beating engines such as are used in the preparation of pulp in the manufacture of paper, and the invention relates specifically to the bars that radiate from the rolls of beating engines, such bars being called beater bars, sometimes fly bars.

For various reasons steel is the preferred metal for beater bars, but some kinds of pulp contain acids or other chemicals that attack ordinary steel beater bars and quickly corrode or otherwise disintegrate the steel. Thus the usefulness of the bars is soon impaired and the bars are eventually destroyed. This not only involves considerable expense for maintaining the beating engines, but it affects the quality of the paper produced from pulps of the kind referred to. For example, pulp that is to be used in making fine white paper is discolored or filled with dark specks by the disintegrated steel. Furthermore, the

2 working edges of the bars, which should have flat surfaces with sharp corners take on rounded contours that prevent their producing the desired effect upon the stock.

In recent years an alloy steel, commonly known as stainless steel, has become available, and while this steel Successfully resists attack by chemicals contained in the pulp the cost of beater bars made of stainless steel, or stainless iron, as it is sometimes called, is so great as to be prohibitive.

The principal object of my invention is to produce beater bars having the desirable qualities of stainless steel bars, but at a cost low enough to make their use permissible. I accomplish this result by using ordinary steel for the lower part of the bar, the part that is embedded in the body of the beater roll, and using stainless steel for the part of the bar that protrudes from the roll.

I shall now proceed to describe my invention in detail, with the aid of the accompanying drawing, in which,

Fig. 1 shows a portion of the end of a beater roll, one bar in the roll being shown in section;

Fig. 2 is a composite view, showing the application of my invention to a particular type of beater bars, in which the lower parts of the bars are ordinary carbon steel and the upper parts are stainless steel;

Fig. 3 shows the lower part of a bar of the type shown in Fig. 2, prepared to receive the stainless steel projections;

Fig. 4 is an end view of one of the stainless steel projections, and

Fig. 5 shows diagrammatically the efiect produced on' ordinary steel bars by chemicals in paper pulp. I

Referring now to Fig. 1, the beater bars as a whole are indicated at"10'-10-1O etc., which bars are arranged around the periphery of the roll in the usual way. As usual the bars are separated by wooden spacers 11- 11-11,which being driven between the bars while the wood is dry, become very tight when the wood becomes wet and-swells. No other part of the roll is shown, nor is any way shown for securing the bars tothe roll body, as these features form no part of my invention, the invention being applicable to any type of roll and any method of securing the bars therein.

Referring now to Fig. 2 it will be seen that the lower part 12 of the bar there shown has the form of a truncated wedge, while the upper part or parts 13 are of invariable thickness. The upper part of the bar is divided into an equal number of crenels and merlons, so called because of their resemblance to the battlements of an ancient castle. This type of bar is not my invention but is shown in Patent No. 1,674,911, Re-issue No. 17,971, to McPhillips. I have chosen to illustrate my invention in connection with the Mo Phillips bar because, first, it is a very efiicient bar, and second, it realizes better than any other bar the purpose of my invention. That is, the benefits of my inventionare attained in higher degree in connection with the McPhillips bar than with any other of which I am aware.

As shown in'Fig. 2 these McPhillips bars are made rights and lefts, so to speak, so that when the bars are mounted in a beater roll with their fiat sides all facing one Way, the merlons and crenels of adjacent bars can be placed in staggered relationship, as in Fig. 2.

In making bars of the McPhillips type according to my present invention I use ordinary carbon steel for the bar 12 and stainless iron or steel for the short bars 13 that form the projections or merlons. These short bars are united to bar 12 by means of intervening strata 14, made also of stainless iron or steel, attached to the bar 12 and to the bars 13 by fusion. See Fig. 1 wherein one of the bars is shown in section and the stratum 14 is seen to have a form resembling an hour glass. Preferably the bars 12 and 13 are rolled steel, While the stratum 14 is cast steel, the latter being formed by the electric arc welding process, as I shall now describe more in detail.

Fig. 3 shows the bar 12 prepared to receive the bars 13, the preparation consisting in beveling both edges of the bar 12 at points where the bars 13 are to go. The edges of the bar 13 are similarly beveled. The bars are then laid on a suitable support, with the apexes of their V shaped edges a short distance apart and welded together by the usual and well known metal-electrode method of electric welding. Preferably the positive conduc tor is connected to the bars and the negative to the welding electrode. This insures. a fused bond between the stratum 14 and each of the bars,

and it insures that the stratum 14 itself will be a dense, flawless casting. Beveling the abutting edges of the bars makes the union between the stratum 14 and either bar longer than-the thickness of the bars, thereby increasing the strength of the union. p

The terms stainless steel and stainless iron are more or less interchangeable, depending upon the carbon content of the metal. The stainless or acid-resisting property of stainless steel ior iron is the result of a high chromium content in the alloy. I have found an iron containing the following alloy satisfactory for beater barsz Carbon (0)"; I .12 maximum 2 Manganese (Mn) .35-.60

'Silicon (Si) .50 maximum Chromium (Cr) 11.50-13.00 Phosphorous (P) .03 maximum Sulphur (S) .03 maximum 3% The metal for the stratum 14, whereby. the bars are united, is obtained from the welding rod, and for this purpose I have found an iron containing the following alloy satisfactory:

Chromium (Cr) 18.00 average 'Nickel (Ni) m 8.00

Carbon (0) .07 maximum Manganese (Mn) .50 maximum Silicon (Si) .50 maximum Sulphur (S) .03 maximum Phosphorous (P) .03 maximum In welding stainless iron or steel to carbon steelit has become the practice to coat thewelding rod with a compound adapted to serve as a 5 -{:flux. While there are other coatings suitable-for this purpose I have found the following effective:

Another satisfactory flux compound isf Aluminum oxide (A1203) or ferric oxide (F8203) 21.02 Silica (SiOz) 31.90 Calcium oxide (CaO) 10.56 Manganese oxide (MnO) 14.85 Zinc chloride (ZnClz) 20.72

In Fig. 1 it will be noticed that the stratum 14 extends below the outer surfaces of the wooden fillers 11, thereby protecting the portion 12 of the 'bar from attack by the chemicals in the beater. The edges of the bars 12 intermediate the bars v13 are not covered, and while these parts are ;stock,remains and protects the bars.

Fig. 5. shows, diagrammatically, the actual contours taken on by two bars that had seen service ina beater. These are extreme cases, it is true, but they indicatethe character of thedisintegration or erosion which results to carbon steel bars from the chemical action. From these examples two'things are. evident: First, a very large quantity of dissolved or disintegrated metal invades the stock inthe beater, with great damage to the color-of the stock, andsec'ond, this conv sumption of themetal quickly deprives the bars of the flat working edges and sharp corners that are so necessary to the; proper treatment'of the stock. 7 7

While I have only shown my invention as it applies to one form of beater bar, it is not to be understood that its application is limited to thisv type ofbar. As isobvious the exposed part of any type of bar .couldbe made of stainless steel and united toa'base-bar of carbon or other suitable. steel by a-stratum'of cast stainless steel. Nor is my invention otherwise limited in its scope by whatprecedes this, its scope being limited only by the appended claim. -What-I' claim is as follows:

A beater bar comprising a bar ofsteel adapted to serve as the lower part thereof, a; bar of stainlesssteel, andan intervening stratum of steel uniting said bars and attached to each by fusion,

said intervening stratum being in cross section substantially the shape of an hour-glass. x

. FRANK M. GLOYD.

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