US2296715A - Hydraulic descaling - Google Patents

Description

J. F. KOMAR Sept. 22, 1942.

HYDRAULIC DESCALING Filed June 15, 1939 a 5 \w 1 6 hwegnlor jf FIE- Zy' @EPH A7148). A W i)? 470/77??? 71 I Patented-Sept. 22, 1942 UNITED Sure nvnnauuc nssosnma 16mm r. Kom'ar, Youlisstowll. om Application June 15. me, Serial No. 219.311 1 Claim. (01. res-1w This invention relates to the hydraulic descaling of hot metal and to the nomles used to elect the sprays required by such work, one of very important. There must be no abrupt angles the objects being to economically effect complete descaling. Other objects maybe inferred from the following disclosure of a speciflc example.

Referring to the accompanying drawing:

Figure l is a side view of a mill including the hydraulic. descaler constituting this example;

Figure 2 is a view of the descaler looking in the traveling direction of the work:

Figure 3 shows one of the descaler nozzles in detail:

Figure 4 is an end view ofthis nozzle;

Figures 5 and 6 are longitudinal sections of the nozzle taken from the lines V--V and VI' -VI in Figure 4; and

Figures '1 and 8 are cross-sections taken from the linesVII-VII and VIII-VIII in Figure 5.

More specifically. the mill constitutes a rollstand i to which hot work 2 is fed over stable 3. Assuming this to be a hot-rolling steel mill, the surface of the work l-will carry tightly adhering scale which, if rolled into the work, will result in a poor flnish. It is the function of the hydraulic descaler to prevent this from occurring by removing the scale iustprior to the entry of the.

work into the rolls.

The descaler includes two pipes 4 arranged I transversely over the top and bottom of the work 2 and provided with nozzles! which eject high velocity water jets against the surface of the work when the pipes I aresuitably connected to a source of waterunder sufllcient pressure.

' Each of the nozzles 5' has an externally threaded end 6 which may be either screwed directly into its mounting pipe 4 or screwed into a bushing I! which is, in turn. screwed into the pipe. If such a bushing is used it should not project any great distance beyond the pipe. The nozzle has a straight longitudinal fluid passage having a circular entrance 'I and initially decreasing in crosssectional area while maintaining its circular shape to a point approximately intermediate its ends. as at, I, the passage then gradually flattening and flaring smoothly without twisting or enlargement of its cross-sectional area to form a slotted exit 8 having straight sides transversely of the passage. As can be seen by reference to Figure 8, the circular part 8 of the fluid passage gradually changes to an oval shape and then smoothly merges into the form required to provide the slotted exit 9.

Water pressures of as much as one thousand pounds Der square inch are usedwith this nozzle,

Monel metal last much longer than when made 1 from metal thatis harder.

the natural resistance of the metal to corrosion,.

such as would tend to cause swirling or directional changes. The portion that decreases in cross-section apparently functions to gradually effect a velocity increase, whereby the water tends tobedrawnintoatrulycircularstream,this then being flattened and flared without anyreduction in velocity until ejection occurs. The result is a flaring wall of'solid water moving at terriflc velocity and being uniform throughout its extent,'both in velocity and cross-section.

The various names are arranged so their slots parallel one another and at such spacing that the various walls of water they produce overlap one another. The entire surface of the steel is subiected to the, overlapping walls ,of solid water.

of the steel. the walls being. however, preferably directed at angles about ib'degrees toward the steels traveling direction. The slots of the various nomles are not in alignment but are arranged at suflicient angularity to prevent the respective flaring walls of water from blending and destroying or nullifying their effects by the mutual interferenoe which would otherwise result.

a further feature of the nozzles is that each is made in one piece ofMonel metal with a wall thickness throughout suiiioient to withstand a fluid pressure of at least one thousand pounds per square inch. Monel metal may be forged to the required shape from a properly drilled and tapered cylindrical blank.

'As previously mentioned," water pressures of up to one thousand pounds per square inch are used in the case of the present invention, al-

though pressures as low as three hundred pounds will function. The actual volume each nozzle individually handles is relatively small, and it follows that with such high water pressures considerable erosion and vibration is to be expected.

It 'has been found thatnozzles made from This is not due to since harder non-corrosive metals have been tried. All that is known is that for some reason Monel metal is notsubiect to rapid erosion or to premature vibration fatigue, these being common faults when other metals are used.

A further advantage in the use of Monel metal is that it is suiilciently ductile and malleable to discovered in connection with the use of Monel metal in that even though machining marks are left in the passage inside the nozzle, the water will within avery few hours erode the surface to smoothness, after which erosion occurs at a very slow rate.

As previously mentioned, the matter of obtaining the wall of solid water contemplated by this invention is very diflicult, and in order to provide the public with positive information as to how to construct the disclosed nozzle so that it functions in the manner disclosed, the following steps in.

its manufacture are outlined:

1. Cut bar of cold drawn Monel metal to proper length. I

Y 2. Drill A" hole completely through center of piece.

3. Drill tapered bore on threaded end /2" deep into A" hole to produce 5%" diameter on open end.

diameter on open end.

(Note: Steps #3 and #4 produce a A;"-length of the original A" bore between two tapered ends.)

5. Turn threaded end to taper for pipe thread.

6. Cut standard pipe thread on threaded end.

7. Heat piece and hand forge spray end flat 4. Drill tapered bore on spray end deep .into A" hole to produce using taper drift .020" thick inside hole to maintain proper inside contour.

(Note: This forging operation must extend back into piece to produce an oval shape in the O ally round 5 4" hole remaining after tapering each end.)

8. Grind flattened end to produce flat face normal to spray center line.

9. Drive tapered drift into spray end to open slot to uniform thickness. This drift is tapered slightly on both its width and thickness to permit entry.

. Although emphasis has been laid on the advantages of nozzles constructed according to the present invention when used in conjunction with water under high pressure, the nozzles will function to produce a flaring wall 01' water or other liquid when supplied the nozzles under lower pressures. Thus, such a nozzle may be used to advantagein applyingpaint or other liquid. However, the invention has been developedin connection with the descaling of steel or other metal, its advantages being particularly evident in connection with this type of work since it functions satisfactorily, whereas all other types of nozzles give considerable trouble.

I claim:

A nozzle characterized by a longitudinally straight fluid passage having a circular entrance and initially decreasing in cross-sectional area while maintaining its circular shape, the passage then gradually flattening and flaring smoothly without twisting or enlargement of its cross-sectional area to form a slotted exit having straight sides transversely of the passage, the nozzle being made in one piece of Monel metal with a wall thickness throughout sufllcient to withstand a fluid pressure of at least one thousand pounds per square inch and having a greater resistance to fluid erosion than if made of harder metal.

JOSEPH F. KOMAR.

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