Патент USA US2405221код для вставки
c. A. M A N N `METHOD 'AND APPARATUS FOR IMPREGNATING `STRIP STOCK Filed April 3, 1944 ATTORNEYS Patented Aug. 6, 1946 , 2,405,221 UNITED vstares PATENT orifice 2,405,221 METHÜD AND APPARATUS FOR IMPREG NATING STRIP'STOCK Cecil A. Mann, Dayton, 0hio, assignor to General Motors Corporation, Detroit, Mich., a corpora tion of Delaware Application April 3, 1944, Serial No. 529,324 " 1 7 Claims. (o1. 117-119) Y This invention relates to a method and appa ratus for continuously applying soft or lower melting point metal to the surface of a metallic strip, and is more particularly concerned with the method and apparatus for continuously ap plying and simultaneously impregnating porous metallic strip material with a lower melting point metal. ' 2 44 respectively. When the level of babbitt ex ceeds the level -of the weirs, the excess babbitt is drained back to a supply tank 46 through con duits 48 and 50 respectively. A supplytank 46 contains a substantial volume of babbitt 40 and also is provided with heating means, not shown, for maintaining the babbitt in the molten condi tion. ‘ An object of the invention is to provide a In order to supply babbitt to chambers 22 and method and apparatus whereby porous strip mae 26, the supply tank 46 is provided with two pumps terial or composite strip material which includes 52 and 54 respectively. These pumps convey a porous metal layer thereon may be continu babbitt from supply tank 40 upwardly through ously impregnated under' sub-'atmospheric con supply conduits 56 and 58 to chambers 22 and» 26 ditions. respectively. The pumps 52 and 54 have suñîlcient In carrying out the‘above object, it is a still 15 pumping capacity to always maintain an excess further object of the invention to carry out the of babbitt ilowing into the chamber so that there vacuum impregnating step while the strip ma is always a return of babbitt through conduits 48 terial is substantially in the ilat condition. and 56. It is also apparent that there will be a This applicationis a continuation in part of leakage of babbitt around the entrance 32 and my copending application, Serial No. 376,512, di 20 exit 38 of the apparatus, which babbitt is likewise rected to a method and apparatus for appli/insr suitably conveyed back to the supply tank 46. molten metal on strip stock. This application is The intermediate chamber 24 is evacuated by directed to somewhat similar subject matten-but means of a vacuum pump 66 which cooperates is modified with particular respect to the Vacuum with the second pump 62 that is immersed in the impregnating step and apparatus whereby the 25 babbitt supply, Pump 62 is utilized to return apparatus is simplified to some extent. » » babbitt leaking into the vacuum chamber 24 Further objects and advantages of the present through openings 34 and 36. Thusthe pump 62 invention will be apparent from the following de while pumping babbitt into the supply tank 46 scription, reference being had to the accompany-4 also induces a vacuum on the intake side thereof ing drawing wherein preferred embodiments of 30 which cooperates with pump 60 to produce a very the present invention are clearly shown. high vacuum in the chamber 24. , In the drawing: It is preferable to supply a reducing gas to The drawing shows a diagrammatic View of a chambers 22 and 26 to maintain as clean a con vacuum impregnating apparatus showing the dition as possible on the surface of the babbitt various pumps and conduits with a strip being 35 whereby oxidation is reduced, if not eliminated. run therethrough. This lessens the amount of sla-g formed and elimi Referring particularly to the drawing, a vac nates the possibility of clogging of the pumps. uum impregnating apparatus is“ shown at 20 In this instance the supply tank 46 is closed to which includes an elongated tunnel-like structure the atmosphere and may either be supplied with broken ldown into three main sections7 namely, 40 a reducing atmosphere thereover or the molten the ñrst section 22, a vacuum chamber 24 and a babbitt may be protected by flotation cf a re third section 26. Sections 22, 24 and 26 are fractory material such as bentonite en the sur aligned and contain entries and exits so that a face thereof. ' strip 30 may pass therethrough in a substantially The pumps 60 and 62 maintain a pressure of ñat condition. Strip 36 enters chamber 22 45 about 2 to 3 mm. of Hg abs. in the vacuum cham through an entrance 32 and leaves through an ber. Reducing atmosphere is admitted to this opening 34 which is an entrance to the vacuum chamber through conduit 63 in suiìcient quan chamber 24. It then passes through the Vacuum tity to bring the pressure in the Vacuum chamber chamber and leaves said chamber through exit to about 7 mm. of Hg abs. The reducing atmos 36 which is the entrance to chamber 26. Finally 50 phere prevents any oxidation of the babbitt in the strip passes out of chamber 26 through exit this chamber. .y 38 In operation, the device is similar to the device .Chambers 22 and 26 contain a predetermined volume of molten metal 46, in this case babbitt, the height of which is controlled by weirs 42 and shown in my copending application, Serial No. 376,512. Strip 36 enters the apparatus through 55 the entrance 32, having ñrst had the surface 2,405,221 3 4 leakage into the vacuum chamber and out of the thereof cleaned of any oxidation, dirt or grease machine, and means cooperating with said ñrst by means of a suitable fluxing apparatus, several mentioned means for partially evacuating said embodiments of which are shown in my copend vacuum chamber and for returning the impreg ing application above referred to. The strip 3i) includes at least a portion thereof Ul nant which leaks out of said throat portions to said supply tank. of porous material which requires impregnation. 2. In a machine for continuously impregnating The strip enters under the surface of the babbitt porous strip material in the substantially nat con 4D in chamber 22 and partial impregnation is dition, an impregnating chamber including throat obtained. This portion of the strip then pro portions at either end thereof for restricting the gresses into the vacuum chamber Where any gasY flow of impregnant therefrom around a strip pass remaining in the pores escapes due to the rare ing therethrough, a communicating vacuum faction of the atmosphere thereover. This causes chamber at the egress end of said first chamber, an impregnating of the babbitt into the pores to means for partially evacuating said vacuum replace any gas which Was evacuated therefrom. chamber, and a second impregnating chamber This portion of the strip then progresses into the chamber 25 where it enters under the surface of the babbitt, and additional babbitt is thereby sup plied to complete the impregnation. The strip then passes out of the exit 3B into a suitable cast connected with the egress end of said vacuum chamber and including throat portions at either end thereof for restricting the now of impreg ’ nant therefrom around a strip passing there ing apparatus, not shown, but described in detail 20 through, a supply tank for containing the im~ pregnant, pump means for pumping impregnant in my copending application Serial No. 376,512. to each of said impregnating chambers said pump 'I‘hiscasting apparatus permits any desired thick ness of babbitt to be cast on the strip,V but forms no part of the present invention. It is manifest fromY the foregoing that a com- . plete impregnationA can be obtained in this ap paratus without any bending of the material'. This is particularly necessary when operating on heavy strips Where the cross sectioned area of the strip is such as to make bending difñcult or im- » possible. The entire operation therefore is car ried out continuously While the strip remains in means having sumcient capacity to maintain a defined level of impregnant in each of said cham bers above the level of said strip regardless of the leakage into the vacuum chamber and out of' the machine, means cooperating with said ñrst mentioned means _for partially evacuating- said vacuum chamber and for returning the impreg nant which leaks out of said throat portions to said supply tank, said last named means being immersed in said impregnant, supply means for providing a reducing atmosphere over the im pregnant in said two end chambers and for pro a flat condition> moving in a single plane. It will be noted that the use of pump S2 elimi nates the necessity of the sump and barometric 35 viding a measured predetermined pressure of re ducing atmosphere in said vacuum chamber. 3. An apparatus for continuously impregnat in that the intake side of the pump balances the ing metallic strip material including a porous vacuum in chamber 2d so that pump 62 cooperates metal layer thereon, said material being in a sub with pump 69' to produce the desired vacuum. Furthermore pump 62 has the additional func 40 stantially flat condition during the imp-regnation tion of removing the babbitt from the vacuum thereof, comprising in combination; a babbitt chamber which babbitt has flowed or leaked chamber adapted to be partially filled with bab. therein from chambers 22 and 25 in returning bitt through which said strip may» pass and in same to the supply tank G5. cluding Ythroats at either end thereof Which It is manifest that in place of babbitt any closely lit the strip as it passes into and out of other lower melting point metal may be utilized, said chamber; a communicating chamber at the lead, tin, antimony, aluminum, or alloys thereof egress end of said ñrst chamber adapted to be may all be used with porous strips having a higher evacuated; means for partially evacuating said melting point whereby substantially complete im communicating chamber, a third chamber at the pregnation is possible. egress end of said second chamber and including While the embodiments of the present invention throat portions at either end thereof, said third as herein. disclosed, constitute preferred forms, it chamber also being at least partially filled with isl to` be understood that other forms might be molten babbitt; a heated supply tank for holding leg utilized in my copending application 376,512 adopted, all c-oming Within the scope of the claims 55 an adequate supply of molten babbitt metal there which follow. 1n; pump means connected with said supply tank lVhat is claimed is as follows: and with said ñrst and third mentioned chambers l. In a machine for continuously impregnating for maintaining the level of babbitt in- said ñrst porous strip material in the substantially flat con and third> chambers substantially constant and dition, an impregnating chamber including throat above the surface of the strip, whereby the molten portions at either end thereof for restricting the 60 babbitt maintains a vacuum seal at the egress end now of impregnant therefrom around a strip pass of the said first chamber and. at the egress end ing therethrough, a communicating vacuum of said second chamber; return means connected chamber at the egress end of said ñrst chamber, with said ñrst and third chambers for returning means for partially evacuating said vacuum chamber, and a second impregnating chamber connected with the egress end of said Vacuum _ chamber and including throat portions at either end thereof for restricting the iiow of impregnant therefrom around a strip passing therethrough, a supply tank for containing the impregnant, pump means for pumping impregnant to each of said impregnating chambers, said pump means having suñicient capacity to maintain a defined level of impregnant in each of said chambers abovelthe level >of isaid’strip regardless of the 65 excess babbitt to said supply tank, a second evac uating means for partially evacuating said com mimica-ting chamber, said last means also having the dual function of pumping babbitt fromv the communicating chamber to said supply tank, said two means. for'partially evacuating the communi eating chamber cooperating to produce the> de-V sired vacuum therein, and means for supplying a reducing atmosphere to said iirst and third cham' bers and a measured .quantity ofrreducing at~ mcsphere to said communicating chamber said 5 2,405,221 quantity being predetermined so as not to re' duce the vacuum appreciably. 4. «An apparatus as claimed in claim 3 wherein weirs are provided in said ñrst and third cham bers to maintain the desired level of babbitt 6 chamber connecting said impregnating chambers, all of said chambers being in substantially the ' same horizontal plane and so constructed that f leakage can occur from said impregnating charn bers into said vacuum chamber around said strip, therein. passing said strip through' al1 of the chambers 5. An apparatus as claimed in claim 3 wherein in substantially flat and unbent condition and in heating means are included in said ñrst and third a single horizontal plane and beneath said im chambers for maintaining the babbitt in a molten pregnant in said impregnating chambers, sup condition. 10 plying sufficient impregnant to each of said im 6. An apparatus as claimed in claim 3 wherein pregnating chambers to maintain the level of said ñrst chamber includes a ñxed Weir for main molten metal constant so that the impregnant taining a defined level of babbitt therein and leakage from said impregnating chambers into wherein said third chamber includes an adjust said Vacuum chamber is compensated for by the able Weir whereby the babbitt level in said third new irnpregnant being supplied into said cham chamber may be maintained at any desirable bers whereby a seal is maintained between said ' depth. chambers and said vacuum chamber and finally '7. In a' method of continuously impregnating removing said leakage from said vacuum cham porous metal strip material in a substantially flat ber whereby the evacuation from said chamber condition, the steps comprising: providing two im 20 is at least partially accomplished by removal of pregnating chambers containing molten impreg nating metal, providing an intermediate vacuum said impregnant therefrom. CECIL A. MANN.