US2808804A

US2808804A - Apparatus for applying metal coatings to valves

Info

Publication number: US2808804A
Application number: US541613A
Authority: US
Inventors: Isler William
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-04-17
Filing date: 1955-10-20
Publication date: 1957-10-08
Anticipated expiration: 1974-10-08

Description

W. ISLER Get. 8, 1957 APPARATUS FOR APPLYING METAL COATINGS TO VALVES Original Filed April 17, 1954 'm'mvwx WILL/AM ASL/5R ATTORNEYS- 2,808,804 APPARATUS FoR APPLYING METAL COATINGS T VALVES V William Isler, Cleveland Heights, Ohio Original application April 17, 1954, Serial No. 425,995, now Patent No. 2,726,165, dated December 6, 1955. Divided and this application October 20, 1955, Serial No. 541,613

3 Claims. (Cl. 118-47) tion of such metal to the seat portions of poppet valves,

for example, to rotate the valves at a uniform rate about a vertically disposed axis, to preheat the area to be coated to a welding temperature by means of gas flames, and to then progressively deposit the molten protective metal at a uniform rate upon successive portions of said area while continuing the rotation of the valve, said protective metal being derived from the melting of welding rods. Such practive is disclosed by way of example, in Wagner Patent No. 2,301,763. a

The aforesaid'rnethod is disadvantageous in the following respects: (1) the necessity of rotating each'valve as the molten protective metal is applied requires the use of a great deal of mechanism, including gears, chains, etc., which are likely to get out of order and require considerable maintenance, (2) the application of protective metal by the gradual melting and depositing of molten drops upon successive portions of the annular preheated zone (see line 55-68, first column, page 3 of the Wagner patent) is rather slow and difficult, particularly from the standpoint of depositing the metal in uniform, predetermined amounts, it being stated in the Wagner patent that the total time required for preheating and coating a valve head about two inches in diameter is approximately ninety seconds, (3) the thickness and uniformity of the coating is extremely difificult to control, so that a large portion of the aforesaid time is taken up by the necessity of spreading of the molten deposited metal by means of the, gas

torches subsequent to deposition of the metal (see line 69- United States Patent 2,808,804 Patented Oct. 8,1957

Fig. 3 is a transverse cross-sectional view, taken on:

the line 3-3 of Fig. 2,'and

Fig. 4 is a transverse the line 44 of Fig. 2.

which may be rotated by any suitable mechanism, such,t

for example, as that disclosed in the aforesaid Wagner patent. The platforml is provided at circumferentially' spaced points with circular recesses 2, in eachof which is mounted an annular worksupporting member 3 of heatrefractory material such as Alundum.

75, first column, page 3','and lines 7-12, second column;

page 3 of the Wagner patent), and (4) the fact that spree.

heating of the area to be coatedto a mere welding te'm perature is not sufficient to enable production robe speeded up toany extent.

The present invention has as its primary object appara- A tus for applying protective metal coatings of the aforesaid character, whereby the articles can be coated at much greater speed than has heretofore been possible, and in a much more eflicient manner, and whereby the thickness and uniformity of the coating are better controlled.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a plan view illustrating more or less diagrammatically one type of apparatus which may be used for practising the invention;

Fig. 2 is a cross-sectional view, at approximately full size scale, taken on the line 22 of Fig. 1;

nate as the coating station, rotation of the platform 1 is stopped until pleted.

When the valve has reached the station S and rotation of the platforml has been stopped, an applicator head, generally designated by reference numeral 8, is placed over the valve, as'shown in the drawings, and is supthe coating of the valve has been comported in the position shown until completion of the coating of the valve. I have not attempted to show means for positioning and supporting'the head 8 during the coating operation, but it will be readily understood that any suitable mechanism maybe provided for this purpose, and that the-positioning, supporting and removal of the head may be effected automatically, and in synchronism with the movements of theplatforrn '1. v

The applicator head 8 comprises a tubular torch or nozzle 9 provided with a multiplicity of circumferentiallyspaced passageways 10 extending through the wall thereof parallel with the axis of the nozzle. 7 a Threadedly secured to the upper end of the nozzle 9 is a hopper member 11 having in its lower end an annular recess or groove 12, which'is in registration with the upper ends of the passageways 10, and is'supplied with a combustible gas mixture through a pasageway 13 extending radially through the member 11. 'The passageway 13 is supplied with gas by means of a conduit 14 secured to the member ll.

The inner cylindrical surface 15 of the' nozzle 9 is Y flush with the inner cylindrical surface 16 of the hoppermember 11, and above the-surface 16, the hopper member 11 is provided with an outwardly and upwardly slop ing conical surface 17.

The hopper member 11 is provided with acover' or cap 18 having an air vent 19, andthe cap is providediwith an annular flange 20 which is interiorly threaded forfl" the upper end of thehoppfer' threaded securement to member 11.

Secured, as by welding, -'to*the central portion of the lower surface of the cap '18 is a tubular member 21 which extends substantially to the lower end of the nozzle '9. The member 21 has a'portion22 of reduced external diameter the outer surface of which forms with the

surfaces

15 and 16 an annular passageway 23, through which powdered metal contained in the hopper ll may be dropped onto the zone 7 of the valve head.

It maybe noted that an annular shoulder '24 is pro-s vided at the upper end of the portion 22 of the member 21, and that the outer peripheral edge of this shoulder bears against the surface 17 of the hopper 11 when thetcap 13 bears against theupper end 25 of the hopper, so as to stop ofi flow of the powder into the passageway 22.

cross-sectional view, taken on When it is desired to feed powder, the cap 18 is unscrewed and the amount of powder fed is controlled by the extent to which the cap isaunscrewed. The member 21 thus constitutes a means forcontrolling, on regulating the quantity of powder fed, as well as a:passageway.-;for thepowder. e U I e The protective metals employed for-coatingthe surs face, 7 of. the valve are preferably selected fromhard facinghigh'temperature metals, of which those described in Cape Patents 2,396,-552;.2;458,5,02"and2,48l,976, are

representative. These have melting points in the range 2400 F.2500 F. Another metal which mays be used.

forthis purpose is a Stellite composition-containing 6% cobalt, 30% chromium, and 4 tungsten, with the remainder iron, silicon and rn'anganese, and having a melting point of .about.240 FQ Thesemetals are preferably in powder form',-and of a rnesh or-size such that they can flow freely into the pasagew'ayil Before the powder is fed.through the passageway 22, and onto the seat portion 7 of the valve, the portion 7 is preheated to a temperature atwhich actual melting of said surface occurs. This preheating is accomplishedby igniting the gases-issuing from the lower end ofrthe passageways 10 andcausing-the. flame thus: produced to heat the surface 7 to the desired temperature. This actual melting of said surface occurs at a temperature very-close to or approximating the melting temperature of the valve material.

Since the passageways 10 are uniformly spaced about the valve seat, the surface 7 is uniformly preheated, without the necessity of rotating the valve. the need: for complicated mechanism usually provided for this purpose.

After the surface 7 has been thus preheated, the flame is reduced in intensity, afterv which powdered metal, in

an amount sufiicient to provide the entire-hard facing for the valve seat, isdropped through the annular pas sageway 22 into the surface 7. Since the surface 7 has been heated to a high temperature, the particlesof powdered metal will become'sintered to the surface 7 and to each other, and in order to remelt the particles and-cause This eliminates 1 them to become bonded tothe surface 7, the flame is again increased in intensity and continued in operationuntil a coating of uniform character is formed. Since the powdered metalis uniformly distributed about the valveseat, and is, uniformly heated-throughout the circumference of the valve-seat; it. is unnecessary to rotate the valve in order to obtain such uniform distribution.

The method, as described, is also advantageous in that it takes considerably less time to coat the valves than isplatform may be stationary, and the applicator head:

moved into position over the valves successively. More-- over, a plurality of applicator heads maybe provided, so that coating of allofthe valves on-the platform 'may beaccoinplished simultaneously. In-this latter case, a single hopper for all of the applicator heads may be provided, as well as a single source of gas for all of the heads, thereby enabling production to be greatly speeded.

It may be noted that if desired, the valves may be individually rotated about their own axes during coating, since the apparatus and method described do not preclude such a possibility.

It is to be understood that various changes may be made in the apparatus hereilrspecifically described without departing from the spirit of the invention of thescope of the appended claims:

on said nozzle, a cover for said hopper member, means asociated with said hopper member and having atubular portion adapted to receive the stem of said valve, said} A tubular portion formingwith the'innersurface of said nozzle a passageway of annular transverse cross-section for the flowiof powdered metal from said'hopperm'ember onto said seatingsurface, and coacting means on said hopper member and last-named'means for controllingthe flow of powder from-said hopper member.

2. Apparatus, as defined in claiml, in which said means associated with said hopper is a tubular member secured to and depending from the centralportion of said'covero 3; Apparatus for applying a protective coating to theseatingsurfaceof'a-poppet-type valve, said apparatus comprising a cylindrical nozzle having inner and outer surfaces and having circumferentially-spaced passageways exte'nding through the nozzleparallelwith the axis of thenozzle, meansfor supplying a'combustible gas-mixtureto 'said passageways, ahopper member mounted on said nozzle and provided with a conical inner'surfaee, a-

cover for said hopper membeiy a' tubular member securedto and depending from the central portion of said cover and having an annular edge adapted to coact'withsaid conical surface to shut off the flow of powder fromsaid hopper, and a tubular sleeve extendingfrom said tubular member andadapted to receive the stem of the valve, said tubular. sleeve forming with the-inner surface of said nozzle'azpasageway of: annular transverse crosssection for-thefiow. of powdered metal-from said hopper member onto said heating surface.

References Cited in the'file ofthis patent UNITED STATES PATENTS 2,049,575

I Sutton 1. Aug. 4, 1936 2,072,845; Benoit Mar. 9, 1937 2,108,998 SChori Feb. 22, 1938 2,301,763- Wagner Nov; 10,1942.

2,317,173 Bleakley Apr. 20,-1 943 2,549,736 Wiese Apr. 17, ll 2,604,356 Saudora July 22,. 1952 2,726,165

Isler Dec. 6, 19 55