US2889803A

US2889803A - Galvanizing means

Info

Publication number: US2889803A
Application number: US588049A
Authority: US
Inventors: William S Pearson
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-05-29
Filing date: 1956-05-29
Publication date: 1959-06-09
Anticipated expiration: 1976-06-09

Description

June 9, 195,9

GALVANIZING MEANS Filed May'ze, 1956 w. s. PEARsoN v 2,889,803

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WXL/[jam ,5. Pearson GALVANIZING MEANS William S. Pearson, Baltimore, Md. Application May 29, 1956, Serial N0. 588,049

6 Claims. (Cl. 118-63) This invention relates generally to improved means and methods in the operation of coating as by galvanizing work-pieces such as pipe or conduit, and particularly has reference to operations involving the removal of excess metal.

Apparatus and method for removing excess galvanizing metal are set forth in my United States Patent No. 2,606,846, issued Augustwl2, 1952. As there shown, the excess galvanizing metal is removed from the work pieces by scrubbing Ithe freshly galvanized work-pieces with internal and external swabbing blasts of uid such as superheated steam, with the blasts directing the excess metal spatter so removed into a cabinet-like collection chamber or so-called spatter chamber or blow box, to be suitably removed therefrom. The spatter of removed excess zinc includes a substantial percentage of dust. The present invention will be described in association with such apparatus, generally as set forth in that patent.

A particular problem in such removed excess zinc arises from the `fact that the zinc dust has a high afnity for oxygen, and the iire hazard involved is therefore significant.

Accordingly, an important general object of the present invention is to provide novel means and methods for reducing the lire hazard in the operation.

In the form of my invention illustrated, t-he re hazard reduction is effected by a pluralityof means, each operative to economically and advantageously reduce the oxygen ratio of the gas or atmosphere in the spatter chamber of the equipment. One desirable means cornprises the diversion into the spatter chamber of the lowoxygen exhaust gas of the zinc pot. Another means is the introduction of a substantially atomized spray of oxygen-absorbing high-flash oil into the spatter chamber, thereby reducing the available oxygen and lowering the oxygen ratio.

Another object of the present invention is to provide novel means for heating the conduit-supporting means engaging freshly galvanized work-pieces, such as drive or conveyor rolls associated with the mechanism for conveying the conduit, thereby economically minimizing the chances of irregular congealing of galvanizing metal as the conduit passes those rolls, preventing the coherence of metal on the rolls, etc. l

Still another object is the provision of common, novel, and, advantageous means for heating the drive mechanism and for reducing fire hazard in the spatter chamber. In a preferred embodiment, this object is accomplished by directing a stream of exhaust gas from the zinc pot to an area which is operatively adjacent both the drive rolls and an opening of the spatter chamber. The characteristic high temperature of such gases heats the drive rolls; and the characteristic low oxygen content offsuch gases provides a low oxygen ratio of the spatter chamber.

A further object is the provision of means to accommodate pressure in the spatter chamber in excess of that tates Patent which can be handled by the exhaust means which normally draws olf the zinc dust from the spatter chamber.

These and other and more particular objects, features, and advantages of the present invention will be readily apparent from the following description of an illustrative embodiment thereof, taken in conjunction with the accompanying drawings, in which:

The single gure-is a generally schematical side elevational view, partially in section, illustrating apparatus for practicing the invention.

By way of example,.the present invention is shown in association with galvanizing equipment shown in my prior United States Patent No. 2,606,846, issued August l2, 1952. As described -in further detail in that patent, the equipment generally comprises a zinc pot 12 at which the galvanizing zinc may be melted for application to work-pieces of pipe or conduit 14 or the like, and metalremoving means such as a generally annularly shaped fluid swab device 15 which is adapted to effect an encircling swabbing blast 16 of iluid externally against the work-piece 14 to remove excess zinc therefrom. Other means (not shown) blows a swabbing blast internally through the work-pieces 14 to discharge therefrom. The metal so removed to a substantial extent sprays vfrom the end of the pipe 14 as indicated by the dust lines 17.

Conveyor or work-supporting or work-driving means such as the conveyor rolls 18, 20, 22 and 24, and conduit driver rolls 26 are shown for effecting `the drive of the conduit 14 from the zinc pot 12 `through the metal removing station provided by Ithe swab device 15, and a take-away conveyor 30 is provided to carry away the fluid wiped conduit sections. A housing or cabinet 32 provides a spatter-chamber or blow boxfof a collection system into which the excess galvanizing metal so removed is directed.

These and other features are more fully set forth and described in my prior patent.

According to a principle and concept of the present invention, there is provided for the spatter chamber 32 a low-oxygen atmosphere or ratio, to minimize any danger of tire or explosion as a result of the high ainity of the zinc dust 17 for oxygen.

Accoringly, as one co-operating feature adapted to provide the low-oxygen atmosphere in the spatter chamber 32, low-oxygen exhaust gases from the zinc pot 12 are shown diverted into a duct 34 having branched passages one of which leads to a stack 36 and the other of which leads through an intermediate duct 38 to the spatter chamber 32. More particularly as shown the intermediate duct 38 leads to a positiongenerally adjacent a spatter chamber opening 40 through which the pipe sections 14 are passed and through which the swabbing stream 16 of fluid `from swab device 15 is projected. Thus the low-oxygen exhaust gas is effectively supplied to the location of origin of the zinc dust 17. As shown, it may -be desirable to form the edge walls 41 of the intermediate duct 38 adjacent the chamber opening 40 in an inclined direction or otherwise direct the flow of the zinc pot exhaust gas toward the chamber opening 40. A confining hood 41a is shown to block escape of the gas.

Such exhaust gas, which originates as a product of combustion of the zinc pot heating gas supplied as by jets 42 associated with the zinc pot, is low in oxygen content by virtue of its combustion in connection with its zinc pot operation, and hence provides an advantageous and economical source of low-oxygen gas. Any suitablewsource of gas low in oxygen content, such as carbon dioxide or other incombustible gas may be utilized, but the exhaust gases from the zinc pot are available at substantially no cost to the operation.

The exhaust duct 34 is desirably provided with a damper 44 whereby the gas may be diverted either to -the stack 36 or to the intermediate duct 33 for supply to the spatter chamber 32.

Further according to the present invention, the high temperature of the exhaust gas coming through the intermediate duct 38 is economically and advantageously utilized in the embodiment shown to heat the driver rolls 26. As is more fully described in my prior patent, heating of the driver rolls 26 minimizes the chances of irregular congealing of the galvanizing metal as the conduit l passes over the driver rolls, and prevents coherence of metal on those rolls.

This driver-roll heating is elected as shown by the heat-transmission adjacency of `the duct 3u with those driver rolls 26.

Auxiliary means are provided for minimizing the oxygen ratio of the gas in the spatter chamber 32, in addition to, and under some circumstances possibly as a substitute for, the exhaust zinc pot gases. As shown, such means comprise a conduit 50 having a dispensing tip or orifice S2 within the spetter chamber 32, and supplied with an oxygen-absorbing oil under pressure. By this means, a ne, substantially atomized spray 54 of the oxygenabsorbing oil may be sprayed into the spatter chamber 32, being therein vaporized and providing an atmosphere that will not support combustion, due to the absorption or combination of that vapor with oxygen in the air of the spatter chamber, Examples of oil which may be advantageously employed for this purpose are high flash oils such as lard oil or parain oil.

A dust collection or exhaust means shown as including an exhaust fan 56 is provided in an exhaust duct 58 leading from an opening 60 in the spetter chamber 32. Through this exhaust duct 58, the exhaust from Vthe spatter chamber is exhausted to a dust collector 62. It Will be understood that the exhaust fan 56 and associated duct Work are of suicient capacity to normally exhaust from the spetter chamber 32 gas as supplied thereto as by the zinc pot exhaust gases through the intermediate duct 3S and by the swabbing stream of fluid from the swabbing devices.

Safety means are provided to accommodate excess pressures which cannot be handled by the exhaust means 56-58- As shown, such means comprise a pressure-relief safety vent 64 or breather, desirably of substantial crosssectional area, leading from .the spatter chamber 32. This provides a stack arrangement or characteristic, so that should the pressure Within the spatter chamber 32 be greater than can be handled by the exhaust system, the atmosphere within the spatter chamber 32 can move up within the safety vent or breather stack 64. Under normal operating conditions, suction of the dust collector means 55-58 is sufficient to prevent the spetter chamber atmosphere from going up the vsafety vent stack 64 and may even draw some air into the spetter chamber 32 through that stack. Thereby is achieved a sort of alternating ilow or breathing action within the stack 64 and between the stack 64 and the spatter chamber 32, as is diagrammatically indicated by the oppositely directed atmosphere-movement indicating arrows 66,

By the apparatus and method of my invention as illustrated, there is .accordingly provided a low or minimum oxygen atmosphere in the spatter chamber, by the economical and advantageous use of the exhaust gases available from the zinc-pot, and by the use of line sprays of oxygen-absorbing liquid directed into the spatter chamber. The pot exhaust gases from the zinc pot are also economically and ladvantageously used to heat the drive rolls for the sections of conduit galvanized.

It is accordingly seen that the present invention pro- 'vides `a new and improved apparatus and method in the removal of excess metal in .the operation of ,galvanizing having the desired advantages and characteristics, and accomplishing its intended objects, including those hereinbefore pointed out and others which are inherent in the invention as described.

It will be understood that modifications and variations may be eiected Without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In apparatus for galvanizing work-pieces, wherein excess galvanizing metal cleaned ofIr said work-pieces is directed into a collection chamber, exhaust means associated with said collection chamber to Withdraw gases therefrom, a pressure relief stack communicating with said collection chamber providing an expansion area for the atmosphere Within said collection chamber that atmosphere in the collection chamber can ovv into said pressure relief stack in the event of pressure in said collection chamber in excess of that which can be handled by the said exhaust means.

2. In work piece galvanizing apparatus including combustion means tor melting zinc for application to said Work pieces and a collection chamber with means for cleaning oi excess zinc from said work pieces and directing said excess zinc into the collection chamber, conduit means for supplying exhaust gas from said combustion means to an opening into said collection chamber to enter therethrough to reduce the oxygen ratio Within the collection chamber, and means for supplying a substantially atomized spray of oxygen absorbing oil into the atmosphere Within said collection chamber to further reduce the oxygen ratio therein.

3. In Work piece lgalvanizing apparatus including combustion means for melting zinc for application to said Work pieces and means for cleaning ol excess zinc from said work pieces including means for relatively movably supporting freshly galvanized portions of said work pieces, the improvement comprising means for supplying exhaust gas from said combustion means to said relatively movable supporting means, including a conduit one end portion of Vwhich is connected to receive the gases from said combustion means and an outlet at the other end portion of said conduit terminating in close proximity to said supporting means to impinge said gases in heating relation upon said supporting means so that marring of said Work pieces as said Work pieces move in contact with said supporting means is avoided and congealing of said zinc to said support means is prevented.

4. In work piece galvanizing apparatus including combustion means for melting zinc for application to said Work pieces and a collection chamber with means for cleaning oli excess zinc from said Work pieces including means relatively movably supporting freshly galvanized portions of said work pieces, means for collecting said excess zinc comprising a collection chamber, means for supplying exhaust gas from said combustion means to said relatively movable supporting means including a conduit, one end portion of which is connected to receive the gases from said combustion means, an outlet at the other end portion of said conduit terminating in close proximity to said supporting means to impinge said gases in heat transfer relation upon said supporting means so that marring of said Work pieces as said Work pieces move in Contact With said supporting means is avoided and congealing of said zinc to said supporting means Yis prevented, and means comprising a hood covering lsaid supporting means for directing said exhaust gases from the said supporting means into said collection chamber to provide a low oxygen atmosphere in said chamber.

5. In apparatus for galvanizing work pieces including combustion means for melting zinc for application to said vvorlt pieces, means nfor applying the molten zinc to Vsaid work pieces, a collection chamber with means for cleaning Qt excess zinc from said Work pieces including means for relatively movably supporting freshly galvanized portions of said work pieces, means for supplying exhaust gas from said combustion means to said relatively movable supporting means including a conduit, one end portion of which is connected to receive the gases from said combustion means, an outlet at the other end portion of said conduit terminating in close proximity to impinge said gases in heat transfer relation upon said supporting means so that marring of said 'work pieces as said Work pieces move in contact with said supporting means is avoided and congealing of said zinc to said supporting means is prevented, means comprising a hood covering said movable supporting means for directing said exhaust gases from the said supporting means into said collection chamber to reduce the oxygen ratio therein, and means for supplying a substantially atomized spray of oxygen absorbing oil into the atmosphere within said collection chamber to further reduce the oxygen ratio therein.

6. A galvanizing apparatus as set forth in claim 5 wherein said conduit has a second outlet, there being a damper at the junction point of said outlets for varying the amount of said exhaust gas directed to said rst mentioned outlet.

References Cited in the le of this patent UNITED STATES PATENTS 1,326,420 Pickens Dec. 30, 1919 2,194,026 Mandle Mar. 19, 1940 2,276,232 Gilbert Mar. 10, 1942 2,579,634 Warren Dec. 25, 1951 2,696,446 Pearson Dec. 7, 1954