US1748518A - Cooling device for valves and the like - Google Patents

Description

b- 30- 'r. MIDGLEY, JR.

COOLING DEVICE FOR VALVES AND THE LIKE Filed Jan. 10,- 1918 m JIIIIIIIIIII I INVENTOR WW 3m Patented Feb. 25, 1930 )UNITED, STATESPATEN'VIJ V oFFIcE;

moms MIDGLEY, m, onznn'zrom'omo, ASSIGNOR, BY JunsNE ASSIGNMENTS, TO nnnoo mom oomrm, or DAYTON, OHIO, A. CORPORATION onnnnawann COOLING DEVICE FOR VALVES AND THE LIKE The present invention relates to improvements in the construction and manufacture of parts of cooling systems or devices in which the transfer of heat from one metallic body 5 to another body is relied upon to produce the desired cooling effect.

As an instance of one articular form of application of such inventlon, the present description relates to valves'of internal combustion engines, which valves are hollow and contain a small amount of worln'ng mercury, which vaporizes in contact with the heated portion of the'valve and condenses in the cooling .portio'n of the valve. Devices of this character are set forth in the applica- "tion of C. F; Kettering, Serial No. 211,156,- filed January 10, 1918, patented March 27, .1928, Patent No. 1,663,709, which describes and illustrates a valve or otherengine part 0 having a body which is subjected to the heat of engine operation, and is formed with a chamber containing a small quantity of working mercury, portionsof which, when vaporized by the heat, pass up the hollow stem of the valve, are there cooled'and returned to the bottom of the valve, which process cools the valve head.

As described more in detail in said Kettering application Ser. No. 211,156, the interior 0 of the valve may be provided with heat dis sipating or transferring surfaces or bodies,

- which may be an amalgam coating or veneer applied to the interior wall of the hollow valve. This coating or veneer appears to have the effect of facilitating the transfer of the heat from the metal of the valve to the working mercury, and vice versa. ..As a result, the mercury is raised to its boiling point more rapidly than would be the case without any such amalgam coating, and begins to function to cool the valve earlier, and before the valve reaches an extremely high temperature. Moreover, when the working mercuryfunctioning to cool the valve, this veneer or coating acts as an eifective intermediary to transfer the heat from the vaporized mercury to the metal of the cooling part of the valve,

thereby cooling or condensmg the vaporized mercury and aiding still further in disslpating the heat.

Amongthe objects ofthe present invem' tion are to provide devices of this character with bodies, or a coatlng, or a veneer, of heat transferring medium which will have marked qualities of heat conduction, mechanical strength, ability to stand up under-the high temperature conditions to which the device is subjected, as well as mechanical vibration, while employing only relatively inexpensive means for attaining these results. Further objects of the invention will be obvious from the ensuing description.

. In order that the invention may be clearly comprehended, reference will now be made to the accompanying drawing which illus-- trates a preferred embodiment of the invention as applied to the valves of internal combustion engines.

In said drawingz- Fig. 1 shows in cross section a valve to which the present invention is applied. Figs. 2 and 3 illustrate the method of hermetically sealin the valve. v

Referring to liig. 1, the steel valve here illustrated comprises the head portion and a stem 12, which may be provided with radiating fins or ribs 13, slipped over the stem in any suitable manner. The head portion 10 may bewelded to the stem 12, so that the head and stem will constitute substantially one continuous piece of metal.

In the interior-of the hollow stem is pro-- 'vided the small portion of so-called working mercury 20, which .vaporizes during the operation of the valve. The vapor passes up towards the top of the stem, where it is cooled and again transformed into its liquid state, dropping by gravity to the bottom of the stem, thus setting up a continuous or cyclican automatic cooling action. A

The inner wall ,of the stem is provided, as shown, with. an intermediate heat transferring medium indicated by the reference number 14,-which forms a coating, veneer or body superposed upon a'ndin intimate contact with the inner face .of said stemchamber for the purpose of facilitating the transfer of heat between the wall and the mercury, and vice versa. This coating is purposely shown on face which can be wetted by the working mercury and has marked advantages, in facilitating the transfer of heat between the wall and the mercury, which appear to be absent when the working mercury is in contact with a surface which it can not wet.

My improvements are directed first toward the securing of the best kind of amalgam for such a coatin My preferred forms of coating are devise both with reference to ability to facilitate transfer of heat, and ability to adhere strongly and permanently to the steel of the wall which supports it, so as to form a structure or coatingwhich is mechanically strong and will not break off or become detached as a result of the vibration and temperature conditions under which the valve operates. These conditions are best met by the use. of an amalgam, including a" metal such as iron, which will strongly adhere to the metal of the valve; in an amalgam of this character, the mercury. of the amalgam facilitates transfer of heat to and from the workingmercury, while the iron of the 14 amalgam facilitates. transfer of heat to and from the steel of the valve, so that the metals of the amalgam, so to speak, form a link or chain system for the easy transfer of heat between the parts.

I have also discovered another characteristic which gives added efficiency to such an intermediate heat transferring medium, viz,

that it should be made of material which b will not only tend to adhere strongly to the steel of the valve, but which, in the event of any part ofthe amalgam becoming disassociated from the steel, will also reassbciate itself and adhere strongly to the steel that may have become exposed. That is, if the amalgam breaks down, (that is, disassociates itself' from the steel,) the coating or veneer becomes automatically renewed without having to replace it or recoat it by an external operation. This property of renewal or recoatingunder operating conditions is hereinafter referred to as the building up property ofthe amalgam. Ihave found that excellent results are to be obtained in practice by employing an intermediate heat transfer medium consisting of an iron amalgam with tin, or such equivalents as lead, or both tin and lead together. I prefer to use an iron amalgam containing thirty per cent (30%) tin lead, which latter serves to protect the iron in the amalgam as above described, and is coated or plated on to the inner walls of the stem chamber in any suitable. manner. In

the use of amalgams containing tin or such.

an equivalent as lead, or both, when any of the amalgamof the veneer breaks down under operatin conditions it becomes mixed with the. working'mercury of the valve, and is carried by the mercury vapor back into contact with that portion of the steel from which the coating, became detached, and

thereby builds up or renews the'coating at the desired point. The best results achieved up to this time have been by the use of an iron amalgam which also contains metals with building up properties, such as tin and lead.

I also obtain improved results by placing a small quantity of an amalgam having building up properties in the working mercury, which amalgamis carried by the heated mercury into contact with any exposed part of the steel of the stem, with which it.

This amalgam which is mixed with adheres. the working mercury may be the same as that which forms the coating or veneer, or it may be one of the components of said'coating or veneer. In practice, I prefer to use a tin or lead amalgam, or a tin-lead amalgam -mixed with the working mercury, and I have obtained excellent results by the use of a tin or tin-lead amalgam mixed with the working mercury in the proportion of 30 to 50 per cent of the-amalgam, in conjunction with a 30%.

to 50% tin-lead amalgam coating or veneer It will be understood that the proportion of tin-lead'present in the working mercury due to the introduction of previously prepared tin-lead amalgam or to the introduction of tin-lead directly, is susceptible of considerable variation, and may vary from nothing as in the case of pure working mercury over a great range as described herein. It will to use building up amalgam in both the Veneer and the working mercury, though this is not necessary since such amalgam, whether originally introduced into the working mercury or originally applied to the stem and subsequently broken loose from the steel, will be eventually carried by the working mercury into contact with any exposed part of the steel to which it will adhere.

amalgams mentioned which contain tin or lead, on account of the lack on the part of the simple iron amalgam, of the property of building up as described above. By using an amalgam of iron with tin or lead or both, the valuable properties of the iron inv adhere apparent from the foregoing that I prefer sion of heat fromthe veneer 14 to the steel ingto the steel andfacili tating the transmishere to the steel; this tin becomes transformed into a tin amalgam when the valve has been in use, as a result of the action of-the working inercur ont etin.

r I may a so us an amalgam veneer 14, for

fwlinstance, iron amalgam, for the valve stem, l

' and place in the working mercur a quantit of another amalgam, which may ave buil ing up properties, for instance, tin-lead amalgam, relying upon the action of the work ing mercury to carry the tin-lead amalgam to the iron-amalgam veneer so as to build it u continuously. The tin-lead amalgam is pre erably present in. the working mercury in such quantity that the proporfion of tin-lead therein is between 30% to The thickness of the coating or veneer may vary in practice; I find that a relatively thin' layer is quite suflicient for the purposes of the invention. 'Theworking mercurymay in some cases be replaced by a tin or lead amalgam, or tinlead amalgam, which, on account of its low boiling point, is able to act as a heat transfer medium in a manner somewhat similar tothe working mercury; or the inside walls of the valve may be rovided with an amalgam coating, employing an amalgam such as described above, without the presence of the working mercury, and the valve will be there-; by. cooled to a certain extent; but I find it always preferable to use the worln'ng mercury along with the amalgam.

The methods of applying the amalgam coatin 'or veneer 14 to the, valve stem are fully escribed and claimed in my divisional application Serial No. 256,530, filed October 4, 1918 patented July 15, 1924, Patent Number 1,501,862. After the talve' stem has been i so;

ner.

provided with its'amalgam coating, as therein described or .ln' -any otherpreferred man -The working mercui'f'is introduced into the valve in the desired quantity, (for example, about five gramsf) and ifit is desired to employ a ua'ntity-o amalgam for the purpose of bur ding up the coating or veneer in the manner herein described, then some. of.

the desired. amalgam, for instance,'tin lead amalgam (about 3 grams), is also introduced along with the mercury. This may be prepared by melting solder into the mercury, and heating, taking care to prevent the formation of oxides. a 1

After the valve has been provided with its amalgam coating and the mercury along valve, it is necessary to seal it hermetically in order to prevent the escape of the vapori'zed mercury when the apparatus is in use.

I prefer to seal the valve by means of a welding operation,'and I also take steps to V.

'withthe amalgam has been placed within the practically hermetically sealed, and I then saw this off even to the top of the valve, -as

indicated by the dotted lin The valve is then placed within threefourths of an inch of the top in water, and

anoxy-acetylefe flame is used to fuse over the entire end-of the valve, after which two more layers of steel are added, 'as shown and indicated by the reference numerals 16 and 17,.and thoroughly fused, While this end of the valve is red hot, it is turnedupside down and the mercury and, amalgam with the mercury is allowed to boil until the boiling ceases. This a plies amalgam to any part. of the coating 0 the upper portion of the stem which may have broken down due to welding, and also'to the end of the plug 15, so that when the valve, has cooled, the

amalgam'coating. will be intact. The method of sealing the valve and of applying the amalgam. coating to the upper portion or the stem and the plug after scaling is described and forms the subject matter of claims in my abovementione d divisional application.

Another advantage of. carrying on this welding process in conjunction with -a water bath, as described above, in order to cause the hermetic sealing of the valve tube, is the avoidance of any possibility of the air within the valve body becoming so heated as the resultJofthe heat of the welding operation, as to cause the blowing out of the plug, as the result of its expansion. The welding mayzi of, course, be effected electrically if desire I believe that I am correctindescribing the metallic coatings'h'ereinas amalgams or alloys of mercury, but it will be understood that I also use the term amalgam herein not only s ecifica'lly but generally, to indicate the '31 03 or mixture of metals which are formed as a result of of manufacture.

-Tin and lead that is, the belong to a chemical series which forms the ourth group in the periodic classification, table. metal or tin are used inthe claimsit'is my improved methods are known as tetrad metals,

Where the terms tetrad to be understood that they include not only tin but such equivalents as lead, or tinlead.

While I have described herein some prefer-red embodiments of my'invention, it will of course be understood that many modifica tions and changes might be made by those skilled in the art without departing from the spirit or scope of my invention as defined by the appended claims. V

What is claimed is as follows:

1. In a device of the kind described; a hollow' metallic portion adapted to be exposed to high temperatures; a metallic working medium contained within said hollow portion which is capable of being vaporized at temperatures to which said hollow metallic portion is subjected when in use; and an inter-- vening building up heat-transmitting medium on the inner wall of said hollow portion, said heat transmitting medium comprising metals common to said wall and to said working medium. 7

. 2. In a device of the kind described a working medium contaiiled within said hollow portion which is capable of bein vaporized at temperatures to which sai hollow portion is subjected when in use; and an in- .tervening heat-transmitting medium on the v inner wall of said hollow portion, said heat transmitting medium comprising metals common to said ferrous metal wall and to said, workingmedium.

'3. In a device of the kind described, a hollow metallic portion adapted to be exposed to high temperature conditions; working mercury within said hollow portion; and an intervening heat-transmitting medium on the interior walls of said hollow portion, said medium comprising an amalgam containing iron;

building up properties; and working mercury contained within said hollow portion.

6. A-body formed with a hollow portion adapted to, be exposed to high temperatures;

. a metallic working medium contained within said hollow portion and capable of being vaporized at temperatures to Which said holing a ferrous metal and 'workin' mercury and an amalgam of said metal withm said hollow portion? 7 v 8. -A device of the kind described comprismg a hollow metallic member adapted tobe exposed to a high temperature and formed of hollow portion of ferrous metal adapted to be exposed to hightemperatures; a metallic low body is subjected when in useand an! intervening heat-transmltting medium on the inner wall of said portion, said mediums containing a quantity of ferrous metal;

7. An engine valve formed "with a hollow p ortion adapted to be exposed tohi'gh tem-' I perature conditions; an amalgam coating having building up properties on the Walls I of thehollow portion; said: coating cpntaim

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