US2211854A - Method of making castings with passages therein - Google Patents

Description

i- 2 1940- v J. A? JOHNSON arm. 2,211,854

METHOD MAKING CASTINGS WITH PASSAGES THERE IN I Filed May 14, 193a- 2 Spats-Shut 1' Eat: IIEIIIIZIIZIIIZII! FZIIIIIIILLII I:

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Aug. 20,1940 J. A. JOHNSON '51-. 2,211,854 HE'I'HOD 0F mum CASTINGS WITH PASSAGES rmai u Filed lay 14, 1938 2 Shoots- 81x001 2 IN ENfORS:

7 ATTOZNEYS'7 Patented Aug. 20, 1940 UNITED STATES PATENT OFFlCE.

mn'rnon or mama cas'rmcs 'wrrn msssoas mama I James A. Johnson, Carter-ct, and Kcnwood Geigcl, Woodbridge, N. 1., assignors to The American Metal Company, Limited, New York, N. Y., a corporation of New York Application May 14, 1938, Serial No. 207,902

4- Claims.

Our present invention relates to a method of making castings with passages therein through which cooling fluid may flow.

tional drill press or lathe drilling methods. How-- I ever, where the castings are relatively large, for

example, 50 inches or more, and not infrequently more than 100 inches in length, through the entire length of which the passage must be formed, current drilling practice does not permit of this being done economically, for two reasons: (1) special drill presses or lathes would be required to drill such castings, and we are unfamiliar with any device which at present is suitable for this purpose; and (2) if any such devicesare or could be made available, it would require a substantial investment to acquire one, or considerable expense and inconvenience would be involved in shipping the castings for drilling at a distant point. f

It has been accordingly proposed to incorporate iron, copper or alloy pipes in the mold set-up for the casting of suchmold walls and to pour the molten metal around these pipes, which are not removed from the casting. Mold walls having such pipes incorporated therein have proven reasonably satisfactory, but in comparison with mold walls having drilled passages therein it was soon recognized that better results could be obtained with the latter since the cooling fluid would be in direct contact with the mold walls and the heat would not have to flow through the pipe wall, the layer of oxides thereon or gas pockets which may have formed therearound, all of which impede the heat transfer from the mold to the cooling fluid.

The present invention accordinglyhas as its primary object to provide a method of forming fluid passages in or through castings of relatively great length. To these ends our method consists in forming the casting around pipes or other cylindrical members and then removing the pipes or other members from the casting after the metal has set or solidified. One practical and economical method which we have developed for More particu-- larly it relates to making relatively large castings,

accomplishing this is to cast the mold plate or wall around pipes through which coolingfluid is kept flowing, and afterthe metal around the pipes has set, to stop the fluid flow through the pipes whereby to permit them to absorb heat 5 from. the casting and to then withdraw the pipes while hot from the casting by applying tension to the pipes to stretch them and reduce their diameter. The method for accomplishing this will be better understood from the detailed junction with the accompanying drawings, wherein we have shown certain preferred means and methods of procedure. In said drawings:

Figure 1 is a side elevation of one form of deis vice for carrying out our invention, parts of the casting mold and the casting therein being shown in section.

Fig. 2 is a side elevation of the device shown in Fig. 1 for applying tension to the pipes, part of 20 said device being shownin section to better illustrate the construction thereof. I

Fig. 3 is a section taken substantially along the plane of the line 3-4 of Fig. 2.

Fig. 4 is a fractional section of a casting show- 25 ing the manner in which the pipe is reduced in diameter during the course of its removal from the casting.

Fig. 5 is a perspective view showing another embodiment of our invention with reference to 0 the device for removing a pipe in a vertical castins, part of said device being broken away.

Figs. 6 and 7 show two difierent side views .of a detail of the pipe tensioning means of the device shown in Fig. 5.

35 Fig. 8 is a fractional detail of the means employed at the bottom of the device shown in F18. 5 for applying tension to the pipe to be extracted.

Referring flrst to Figs. 1' to 4 of the drawings. let the numeral l0 represent a mold for casting plates of copper or the like ll .of relatively great length within which pipes I! are cast. Preferably the mold is of the separable wall or section type, and comprises a base plate It, side walls l4 and end walls l5 suitably held in assembled relation by means (not shown). The end walls l5 are formed with openings it through which the pipes l2 snugly flt and may be suitably packed and by which end walls the pipes are supported in the mold when set up. Preferably the pipes are formed at their ends with transverse openings l1 and I8 extending in spacedrelation at right angles to each other for a purpose which will presently appear.

In casting the plate II the mold de- 10 scription which follows, when considered in conlll'issetup with the pipes I2 supported in the end walls I5 and with the ends of the pipes connected to a water supply to circulate water therethrough, and while the water is thus flowing through the pipes the molten metal is poured into the mold to envelop the pipes. The how of water is continued until the casting has set; whereupon the flow is cut off to permit the pipes to absorb heat from the casting which is still red hot. As soon as the pipes reach the temperature of the surrounding metal, the extraction of the pipes is proceeded with. The water connections to the pipes are removed and the tensioning means indicated as a whole by the numeral 20, consisting of a framework and tensioning means which will now be described, are applied to the pipe ends.

The framework or support has a substantial flat base 2| and a cylindrical head, 22 connected together by bracing elements 23. The base 2| has a central opening 24 through which the pipe l2 may extend, and the cylindrical head has a central opening 25 through which extends a tensioning screw 26, one end of which carries a bushing 21 having transverse openings spaced at right angles to each other for mounting in coincident relation to the openings l1 and i 8, and through which pins 28 may extend to connect the threaded member 28 to the end of the pipe l2. Threaded on the outer end of the threaded member 28 is a hand wheel 29 having a screw-threaded hub 80, the inner end face 3| of which acts. as a bearing surface for providing reactive contact with the outer end 32 of the cylindrical head 22. However, to reduce the friction of such engagement to a minimum, we prefer to interpose between the reactive surfaces 3| and 32 an anti-friction bearing 33 which may be suitably held against the end face 32 by a pair of cleats 34. The antifriction member 33 has an axial opening through which the screw-threaded member 26 extends.

In preparing to withdraw a pipe from the casting the tensioning means 28 is placed in position by passing the opening 24 in the base thereof over the end of the pipe l2 and then coupling the bushing 21 to the pipe end by the pins 28. Thereupon, by rotating the hand wheel 29 in a clockwise direction to bring the bearing surface 3| into contact with the anti-friction bearing 33, tension will be applied to the pipe [2 to stretch it and reduce its diameter, as best shown in Fig. 4. In withdrawing the pipe, it will be understood that ends of the pipe protruding beyond the casting are comparatively cold, while the pipe inside the casting is at a higher temperature. In the case of a copper casting with steel pipes, the casting and pipes inside are both at a good red heat. When now the pull is applied to the cold end, the point adjacent to the edge of the casting will neck down or reduce in diameter first, because it has the lowest frictional force to resist movement and yet has practically the same temperature as the interior of the pipe. As soon as this neckingdown occurs, the smaller diameter portion (being separated from the casting proper) begins to cool and becomes stronger, so the adjacent increment of pipe,--now having the lowest frictional and adhesive force to resist movement, necks-down and so the reduction of diameter progresses until the whole pipe is of a smaller diameter, except the two ends whichare the original diameter. One of these may now be sawed of! and the tube withdrawn. If desired, the pull or tension may be applied at the opposite ends of the pipe. It may happen that in so applying tension, the pipe may break intermediate its ends and thus permit its ready withdrawal from the casting without resorting to a pipe cutting operation.

Referring now to Figs. 5 to 8 of the drawings, the tensioning means therein disclosed is somewhat analogous to that already described, and primarily difiers therefrom in that instead of each end of the pipe I 2 being formed with transverse openings for engagement by a bushing on the tensioning member, the upper end 01' the pipe l2 has a ball 36 welded thereto for cooperation with a pin 31 which is adapted to pass through the walls of a u-shaped member 38 to engage the bight of the bail. The U-shaped member 38 is carried by a tensioning screw 38 which passes through the head 40 of a bracing member having legs 4! and bases 42 adapted to seat against the top of the casting. Threaded on the tensioning screw outwardly of the head 40 is a hand wheel 43 adapted to be brought into reactive engagement with the head 48. To reduce the frictional engagement between said members, an anti-friction member 44 somewhat similar to .that previously described, may be employed.

Preferably the outer end of the tensioning screw is formed with an eye 45 for engagement by the hook on a crane (not shown) for applying a pulling force to the pipe either initially or after it has been preliminarily stretched by the tensioning means described.

In the use of the tensioning device shown in Figs. 5 to 8 it frequently happens that the pipe in being withdrawn breaks intermediate its ends thus necessitating the removal of the retained portion of the pipe in the lower section of the casting. To accomplish such removal we provide at the bottom of the casting a jackscrew arrangement, indicated generally by the reference character 46, which permits or applying tension to the lower end of the pipe. This jackscrew arrangement consists in first threading a pipe section 41 having an external thread to the lower end of the pipe l2 and then welding said pipe section to said pipe l2, as indicated at 48. Screwthreadedly engaging the external threads at the lower end of the pipe 41 is a jacknut 48 which is threaded onto a nipple II, which, in; turn, is welded, as indicated at II, to the upper end of a fluid supply pipe 52. Between the top end of the jacknut 49 and a washer 53 engaging over the lower end of the pipe l2 and seating against the bottom face of the base section of the mold, is a spacer pipe 54 which serves as a reaction member analogous .to the parts 40 to 42 above described.

The mode of applying tension to the bottom of the pipe is quite analogous to that applied to the top of the pipe in that by turning up the Jacknut 49 against the spacer pipe 54, tension will be applied to the pipe 41 which will be communicated to the pipe I2 to stretch the latter.

In the use of the form of the invention shown in Figs. 5 to 8 it will be apparent that the pipe may be first tensioned at its bottom in the manner described and the tensioning means at the top thereof then employed, or vice versa. It may also be practicable to dispense with the specific tensloning means at the top of the pipe and rely solely upon the crane for suppl ing the necessary tension to stretch and withdraw the pipe from the casting.

In carrying out our invention we have found that the passages formed in the casting can be made relatively smooth if the pipe, before being placed in the mold, is first painted or coated with bone ash or other suitable mold dressing and dried in any desired manner, for example, by which cooling fluid is circulating and after the first passing steam or hot gas through the pipes. Pipes, when so treated, and withdrawn from the castings, were found to be relatively free from copper adhesions.

From the foregoing detailed description it will be apparent that we have provided a relatively simple method of forming castings of relatively great length with fluid passages therein, and while we have shown and described certain preferred embodiments of our invention, it is to be understoodthat we do not wish to be limited to the specific methods of procedure or devices used therewith since these maybe varied within the range of engineering skill without departing from the spirit of our invention.

What we claimis:

1. The method of forming a duct or passage in a casting, which comprises forming the casting around and in direct contact with a tube through casting has'set but is still at a high temperature,

stopping the fluid circulation therethrough to permit the tube to absorb heat from the casting and then applying tensile stress to the tube to stretch it to permit its withdrawal from the cast- 2. The method according to claim 1, wherein the tube is permitted to attain the temperature of the casting before the tensile stress is applied thereto,

3. The method according to claim 1, wherein the exterior surface of the tube is coated with a mold dressing material and dried before the metal is cast therearound.

4. The method according to claim 1, wherein the tensile stress is applied to the ends of the tube.

JAMES A. JOHNSON. KENWOOD GEIGEL.

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