US3749152A

US3749152A - Direct chill casting mold manifold apparatus

Info

Publication number: US3749152A
Application number: US00171461A
Authority: US
Inventors: J Dore; C Mcnutt
Original assignee: Olin Corp
Current assignee: Olin Corp
Priority date: 1971-08-13
Filing date: 1971-08-13
Publication date: 1973-07-31
Anticipated expiration: 1990-07-31

Abstract

A direct chill casting mold assembly comprising a mold liner and a mold manifold. The mold manifold has at least two cooling medium chambers. A first chamber communicates with a source of cooling medium under pressure. Means are provided intermediate the first and second chambers for conducting the cooling medium from the first chamber to the second chamber. A substantial pressure drop is generally taken across the conducting means. Means are also provided which communicate with the second chamber for siphoning the cooling medium from the second chamber and applying it to a surface of the mold liner. The pressure loss between the two chambers assures uniform water distribution about the mold liner periphery.

Description

United States Patent [1 1 Dore et al.

[ DIRECT CHILL CASTING MOLD MANIFOLD APPARATUS [75] Inventors: James E. Dore, Milford; Charles R.

MeNutt, l-lamden, both of Conn.

[73] Assignee: Olin Corporation, New Haven,

Conn.

[22] Filed: Aug. 13, 1971 [21] Appl. No.: 171,461

3,065,999 WugstuiT et ul 164/283 [451 July 31, 1973 Primary ExaminerRobert D. Baldwin AttorneyRobert H. Bachman et al.

[57] ABSTRACT A direct chill casting mold assembly comprising a mold liner and a mold manifold. The mold manifold has at least two cooling medium chambers. A first chamber communicates with a source of cooling medium under pressure. Means are provided intermediate the first and second chambers for conducting the cooling medium from the first chamber to the second chamber. A substantial pressure drop is generally taken across the conducting means. Means are also provided which communicate with the second chamber for siphoning the cooling medium from the second chamber and applying it to a surface of the mold liner. The pressure loss between the two chambers assures uniform water distribution about the mold liner periphery.

40 Claims, 6 Drawing Figures Patented July 31, 1973 49,152

4 Sheets-Sheet 1 INVENTOR JAMES E DOPE f --l /g! 0104mm A. Mc/VUTT ATTORNEY Patented July 31,1973 3,749,152

4 Sheets-Sheet 2 \J INVENTORS JAME .0095

CHARLE MC Nun ATTORNEY Patented July 31, 1973 4 Sheets-Sheet INVENTOR JAMES E. DORE CHARLES R. MCNUTT ATTORNEY Patented July 31, 1973 ,4 Sheets-Sheet 4 FE R32 853 Sn fi s: M6 EMEEMQ $32? 825% v 2 2 wm Q S Q Q JAMES E DORE CHARLES R. Mc NUTT INVENTORS BY/ 2 fi ATTORNEY O Q Q DIRECT CHILL CASTING MOLD MANIFOLD APPARATUS BACKGROUND OF THE INVENTION This invention relates to the field of direct chill casting of metals, particularly aluminum, aluminum-base alloys, copper and copper base alloys. The invention is directed to a chill casting mold assembly comprising a mold liner arid mold manifold for applying a cooling medium to a surface of the mold liner. The mold assembly in accordance with this invention obtains a uniform distribution of coolant around the periphery of the mold.

Uniform water distribution, particularly in extrusion ingot molds, contributes significantly to increased casting speeds, better ingot surfaces, improved ingot internal structure and to reduced die wear and superior extruded surfaces.

The mold assembly in accordance with this invention also provides improved productivity because its slim profile permits the nesting of molds in a honeycombed fashion, thereby providing a substantial savings in space.

Single chamber mold manifold systems are nearly universally employed today. In a single chamber mold manifold system, cooling medium is supplied under pressure to a manifold chamber and is discharged from the manifold chamber through an annular slot and applied to a surface of the mold liner. A single chamber manifold is subject to nonuniform water distribution even with the use of baffles or weirs. As one makes the single chamber design more compact, the uniformity of water distribution decreases. This situation arises because the directionality of water flow vectors is intensitied in smaller water chambers. As directionality increases, the nonuniformity of water delivery around the mold periphery becomes greater.

Further, in single chamber manifold systems, the control of water flow and water distribution is determined by pressure drop across the annular water discharge slot. The slot width is generally limited to 0.010 to 0.015 inch and this small slot size makes alignment extremely critical and thus precludes use of this type of mold assembly for casting ingots of reasonably large cross section.

SUMMARY OF THE INVENTION In accordance with this invention, a direct chill casting mold assembly has been developed which eliminates the aforenoted problems of the prior art assemblies. The mold assembly of this invention comprises a mold liner and a mold manifold having at least two water chambers.

A first chamber communicates with a source of cooling medium under pressure which is generally water. Means are provided intermediate the first and second chambers for conducting the cooling medium from the first chamber to the second chamber. Generally speaking, a substantial pressure drop is taken across the conducting means. The conducting means preferably comprises a plurality of distribution holes. Means are also provided which communicate with the second chamber for siphoning the cooling medium from the second chamber and applying it to a surface of the mold liner. The siphoning means generally comprises a leg which is formed between the mold liner and the manifold and communicates with the second chamber by means of siphon ports at one end and is provided with an annular cooling medium discharge slot at its other end.

Because the mold manifold system of the invention operates on the principle of the siphon, relatively large annular cooling medium discharge slots can be employed while maintaining uniform cooling medium flow around the periphery of the mold. It has been found that with the mold assembly of this invention, slight variations of the slot width due to misalignment do not measurably affect the uniformity of water distribution.

.T he mold assembly of this invention overcomes flow directionality problems by utilizing at least two water chambers as opposed to the single chamber units of the prior art. In the double chamber design of this invention, the pressure loss between the two chambers assures uniform water delivery around the mold periphery. Further, the directionality of the incoming water is hydraulically damped in the two chamber system.

Accordingly, it is a principal object of this invention to provide a direct chill casting mold assembly having improved uniformity of distribution of water about the mold periphery.

It is another object of this invention to provide a mold assembly as above, wherein the mold manifold has at least two chambers.

It is a further object of this invention to provide a mold assembly as above, wherein the cooling medium is applied to the mold liner by a siphoning action from the mold manifold.

It is a still further object of this invention to provide a mold assembly as above, having a slim profile, thereby permitting the nesting of mold assemblies in a compact fashion.

Other objects and advantages will become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partial cross sectional view of the mold assembly of this invention.

FIG. 2 is a partial top view of a direct chill casting table having a plurality of mold assemblies of this invention nested therein.

FIG. 3 is a perspective exploded view of the mold assembly of this invention.

FIG. 4 is a partial cross section view of the mold manifold.

FIG. 5 is a cross sectional view of a mold assembly in place and related casting equipment during direct chill casting.

FIG. 6 is a graph illustrating the uniformity of cooling medium distribution about the periphery of the mold of this invention as compared with a prior art assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and especially to FIG. I, there is illustrated a typical direct chill casting mold assembly I in accordance with this invention. The mold assembly I comprises a mold liner 2 and a mold manifold 3. The mold manifold 3 supplies cooling medium, generally, water, which is applied to a surface 4 of the mold liner 2. Water will be employed as the cooling medium in the remaining description, but the invention is not limited thereto. The cooling medium forms no part of the invention and any desired cooling medium as are known in the art could be employed.

The mold liner 2 comprises a header portion 5 and a mold portion 6. Preferably, the mold liner 2 is an integral one piece casting, though other mold liner designs well known in the art could be employed.

A shoulder 7 is preferably provided at the top of the back wall 4 of the liner 2. This shoulder provides for self-centering of the liner 2 within the mold manifold 3 assuring concentricity of the liner and manifold.

The bottom of the mold liner is chamfered at 8 to define between the mold liner 2 and the mold manifold 3 a water discharge slot 9. By assuring the concentricity of theliner 2 and manifold 3, a uniform width of the water discharge slot 9 is obtained.

As shown in FIGS. 2 and 3, the mold header 5 preferably has a polygonal shape such as the pentagonal one shown. This allows the mold assemblies 1 to be nested in a honeycombed fashion in a casting table T and, thereby, obtain the closest packing and greatest density of mold assemblies for a given area. The pentagonal shape is particularly adapted for use wherein the two rows of mold assemblies 1 are employed as shown in FIG. 2. However, if more than two rows were to be employed, hexagonal header portions 5 for at least the internal rows would provide the closest packing. The close center-to-center ingot spacing obtainable with the inventive mold assemblies 1 is as much as twothirds less than that obtainable with typical prior art mold assemblies.

The mold manifold 3 of FIG. 1 contains at least two cooling medium chambers 10 and 11. The first chamber 10 communicates with a source of water under pressure by means of inlet 12. Means 13 are provided intermediate the first 10 and second 11 chambers for conducting the water from the first chamber into the second chamber.

This conducting means 13 generally comprises a plurality of distribution holes substantially equally spaced about an annular web W between the two chambers 10 and 11. The distribution holes 13 are generally sized such that a substantial pressure drop occurs across them. The length to diameter ratio of the distribution holes is preferably greater than 2 with the optimum at about 3. The pressure drop across the distribution holes 13 is preferably at least five times the pressure drop in any other downstream portion of the mold manifold 3 system and, still more preferably, the pressure drop between the two water chambers 10 and 1 l is from about 5 to 20 psi, with the optimum at about 7 psi.

Siphoning means 14 communicating with the second chamber 11 is provided for siphoning the water from the second chamber and applying it to a surface 4 of the mold liner 2. Preferably, the siphoning means 14 comprises a plurality of siphon ports 15 substantially at one end of a siphon leg 16 defined by the back surface 4 of the mold liner 2 and the inner surface 17 of the mold manifold 3. The siphon ports 15 are substantially equally spaced about the inside periphery 17 of the mold manifold 3.

An annular ledge 18 or lip is provided as best shown in FIG. 4 about the inside surface 17 of the mold manifold 3 at the discharge end of the siphon leg 16. The slot 9 defined by this lip 18 and the chamfered portion 8 of the mold liner 2 comprises the annular water discharge slot 9.

The width of the annular water discharge slot 9 may be set as desired and is generally at least 0.030 inch and, preferably, on the order of about 0.060 to 0.090 inch wide.

As aforenoted, a substantial pressure drop is provided across the conducting means 13 or distribution holes; however, a relatively insignificant pressure drop is obtained across the siphon ports 15 and the cooling medium discharge slot 9, preferably, less than 1 psi with the optimum at about 0.5 psi. This permits the size of the siphon ports 15 and the discharge slot 9 to be relatively large as compared to known assemblies.

Referring again to FIG. 3, the manifold 3 is preferably formed of a casting; however, it may be formed by any desirable techinque known in the art, for example, as by welding pieces together to obtain the structure shown. When the manifold 3 is formed preferably as in FIG. 3, the top 19 and bottom 20 surfaces are open in parts and contain slots 21 or holes which communicate with the chambers 10 and 11.

The slots 21 are formed by virtue of casting practice and in order to be able to clean or otherwise maintain the manifold structure. The slots 21 do not form a part of the instant invention and need not be present. However, when an open manifold is employed, referring to FIGS. 1 and 3, it is necessary to seal these slots 21 or openings by employing a gasket 22 between the mold liner 2 and the upper surface 19 of the mold manifold 3 and by employing a gasket 23 and cover plate 24 cov ering the openings in the bottom surface 20 of the mold manifold 3.

Referring again to FIG. 4, it is seen that the first chamber 10 is-considerably longer than it is wide, preferably, the length-to-width ratio of the first chamber is greater than 2 to l. The same applies for the second chamber 11 with the second chamber having an even greater length-to-width ratio than the first chamber 10. Preferably, the length-to-width ratio of the second chamber is greater than 3 to l with the optimum at about I2 to 1. By employing such a design, it is possible in accordance with this invention to obtain mold assemblies having very slim profiles.

In practice, for an 8 inch diameter mold, it has been possible to employ widths in the first chamber 10 as narrow as five-eighths inch and widths in the second chamber 11 as narrow as three-eighths inch and to provide overall thickness from the inside mold wall 25 to the outside manifold wall 26 of only l-3/ l 6 inch. These dimensions are exemplary of the slim profiles which can be obtained with the mold assembly I with this invention and are not meant to be limitive thereof, and may be varied as desired.

The mold assembly 1 of this invention provides a favorable pressure drop ratio between the pressure drop taken across the conducting means 13 or distribution holes and the pressure drop taken across the siphon ports 15 and the annular water discharge slot 9 and, thereby, assures uniform distribution of water around the periphery of the mold.

The minimum practical water flow discharged from each mold is preferably 0.6 gpm/inch of periphery of the water discharge slot (gpm gallon per minute). Thus, for an 8 inch diameter mold 1 having a 25 inch slot 9 periphery, the lowest practical flow rate is somewhat less than 15 gpm. A continuous water curtain will be maintained at this low rate of coolant delivery.

The maximum flow rate is defined essentially by the quantity of water needed for casting and the head capacity of the pumps. Preferably, for aluminum and aluminum base alloys, the total water flow rate in gallons per minute to weight rate of metal being cast in pounds per minute is from about 0.2 to 2.5 gallons per pound with the optimum volume at about 0.5 gallons per pound. Reasonable casting practices will not normally require more than 1 gallon per pound of metal being cast.

The conducting means 13 or distribution holes allow the water entering the second chamber 11 to be delivered uniformly around the periphery of the manifold 3. The primary purpose of the second chamber 11 is to dissipate the velocity head of the water exiting from the distribution holes 13. By providing the long narrow flow path in the second chamber 11, quiescent flow is obtained through the siphon ports 15.

The siphon ports 15 which are relatively large feed the water to the siphon leg 16. The water flows down the siphon leg 16 and is applied to the ingot through the discharge slot 9. Flow control is accomplished by regulating the amount of water delivered to the first chamber and the pressure drop across the conducting means 13 or distribution holes. The second chamber 1 l and siphon leg 16 act as a barometric leg and remain full of water at all times. By providing the water flow into the siphon leg 16, by the siphon principle the uniform water distribution achieved by the pressure drop between the two chambers 10 and 11 is retained.

The mold assembly 1 of this invention is particularly useful in the casting of aluminum, aluminum base alloys, copper and copper base alloys, though its application is not limited to these metals and alloys. By virtue of the fact that the mold assemblies 1 of this invention can operate at relatively low water flows, they overcome a severe problem in prior art designs when casting stress sensitive aluminum alloys of the 2,000 and 7000 series. Such alloys are prone to cracking during direct chill casting, particularly as the transverse ingot cross section increases.

As a general rule, stress sensitive aluminum alloy ingots with a minimum transverse dimension of 14 inches or more cannot be cast consistantly in production with a high ingot recovery, namely, 95 percent or more unless cooling water rates are on the order of 0.4 gallons per pound of aluminum cast or less. Single chamber mold manifold units do not operate reliably at this low flow level.

The mold assemblies 1 of this invention on the other hand have shown that operation at 0.4 gallons per pound of aluminum is entirely feasably and, in fact, satisfactory performance prevails at rates as low as 0.2 gallons per pound of aluminum cast. Consequently, the design of this invention provides improved ingot recoveries when used for casting stress sensitive alloys.

Referring again to FIG. 1, it has been found that preferably the ratio of the length of the first water chamber 10 to the diameter of the water inlet 12 is greater than or equal to l to l with the optimum value at 2 to 1. Further, it has been found that preferably the ratio of the width of the second chamber 11 to the diameter of the distribution holes 13 should be greater than 1-5: to l with the optimum value at about 3 to l.

The length of the mold portion 6 may be set as desired in accordance with known practices in the art; however, long mold lengths increase the tendency for warpage of the mold liner 2 and promote the use pf higher molten metal heads in the mold which have an adverse effect on billet surface quality.

In accordance with this invention, the mold length is preferably the minimum practical length necessary to provide adequate time for filling and solidification of the molten metal in the mold at the start of a drop. The optimum mold length 6 has been determined to be 4-5: inches or less. A short mold length such as this allows for high speed casting with excellent surface quality.

Referring to FIG. 5, there is shown a mold assembly 1 of this invention during the casting operation. The mold assembly 1 is set in a table T such as that shown in FIG. 2 and the water inlet 12 is connected to a source of water under pressure.

The molten metal M is delivered to the mold by a novel nozzle 30 and conical flow distributing means 31 which is the subject of companion US. Pat. application Ser. No. 171,462, filed of even date herewith by Peter E. Sevier, assigned to the assignee of the instant invention.

The novel distribution mechanism comprises a nozzle 30 which is connected to a source of molten aluminum such as a launder 32 at one end and at the other end is immersed in the molten aluminum Min the casting assembly 1. A conical distributor 31 is held under the nozzle 30 by means of a Marinite float 33. The nozzle protrudes through a hole 34 in the Marinite float 33 with the diameter of the hole 34 being only slightly larger than the diameter of the nozzle 30. By virtue of this relationship the alignment between the conical distributor 31 and the nozzle 30 is readily maintained.

Further, the float 33 and cone 31 regulate the flow of aluminum into the mold liner 2 since as the aluminum level in the mold rises carrying the float 33 with it the conical distributor 31 reduces the flow or entirely shuts it ofi.

As shown in FIG. 5, the molten metal M solidifies about its outside surface 35 such that the outside surface is sufficiently solid to maintain the integrity of the casting C after it has passed the end of the mold liner 2. As shown, the interior 36 of the casting is still molten when the casting has dropped below the end of the mold liner 2.

Casting is initially begun by employing a bottom block as is known in the art which sits up within the mold liner 2 until the casting C has sufi'iciently solidified to begin the drop. The length of the casting is dictated only by the facilities, namely, the melting capacity and space available. As shown in FIG. 2, a plurality of castings may be poured from a single melt by employing a cluster of mold assemblies 1 as shown.

The drop rate or casting rate is significantly improved by employing the mold assemblies of this invention because of the improved efficiency of the cooling medium distribution.

FIG. 6 illustrates the improved uniformity of peripheral distribution of water around the mold assembly 1 of this invention over a wide range of flow rates as compared to a prior art single chamber mold assembly commonly used in the field. Flow tests were run at water flows of 20, 30 and 45 gpm.

The mold assemblies 1 of this invention produce a continuous water curtain at 20 gpm and an extremely uniform water distribution. By contrast, the water distribution of the prior art mold was very poor. The flow pattern from this mold at 20 gpm and all other flow rates was ragged and discontinuous.

In FIG. 6, the solid lines represent the flow rates of water issuing from the water discharge slot 9 as a function of slot position around the periphery of the mold. The dashed lines present similar data for prior art molds.

It is noted that at one point, no flow issued at all from the prior art mold. Neglecting this point, however, the variation in flow as a function of position around the periphery prior art mold is about i 40 percent. at 20 gpm, :2 75 percent at 30 gpm and i 100 percent at 45 gpm. This compares with a variation in water flow for unit slot length at all flow rates for the mold assemblies of this invention of less than i I percent.

These data point out the clear superiority of the mold assemblies I of this invention as compared to typical prior art single chamber manifold mold assemblies.

The invention has been described with reference to cylindrical type molds; however, it is also applicable to other mold shapes such as sheet or slab molds.

Molds for sheet or slab ingots and other noncylindrical shapes also require uniform water distribution with the exception of the corners where the cooling surface to volume ratio varies from the broad faces and end faces. Comer conditions are readily handled by blocking and reducing water flow. The problem in noncylindrical molds is to achieve uniform distribution of cooling medium at the broad faces and end faces of the mold. This problem can be solved by employing the novel mold manifold siphon leg cooling means of this invention.

The mold manifold assembly 1 of this invention as applied to noncylindrical molds would have a cross section substantially the same as that for a cylindrical mold as shown in FIG. 1, except the periphery of the mold liner 2 would be noncylindrical and the manifold 3 would conform to the noncylindrical shape of the mold liner 2.

In the mold manifold assembly 1 shown in FIG. 1, the mold liner 2 extends over only a portion of the length of the mold manifold 3. This is not meant to be limitive of the invention and the length of the mold liner 2 as compared to the mold manifold 3 may be set as desired by merely providing the lip 18 at an appropriate position on the inside wall 17 of the mold manifold 3 to form the annular water discharge slot 9.

It has been found that the cross sectional area of the inlet 12 should be greater than or equal to the sum of the cross sectional areas of the distribution holes 13 in order to assure proper and complete filling of the first chamber 10.

The materials employed in the various parts of the mold manifold assembly of this invention are the same as those used in conventional direct chill casting mold assemblies.

The prior art single chamber mold manifold mold assemblies have been described with reference to the use of an annular water discharge slot since a similar means is preferred for use in accordance with this invention. However, sometimes, prior art mold assemblies employ a plurality of small diameter holes equally spaced about the periphery of the manifold in place of a discharge slot. When holes are used, hole size is also limited generally to a maximum diameter of about three thirtyseconds inch. I-Ioles of this size are very susceptable to plugging.

Length measurements as described above are measured in the direction of casting, or more specifically, metal travel through the mold portion 6.

It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are suitable of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined'by the claims.

What is claimed is:

1. In a direct chill casting mold assembly comprising a mold liner and cooling means for applying a cooling medium to a surface of said mold liner, the improvement wherein said cooling means comprises:

a manifold having at least a first and a second chamber, said first chamber communicating with a source of cooling medium under pressure;

means intermediate said first and second chambers for conducting said cooling medium under pressure from said first chamber to said second chamber, a substantial pressure drop being taken across said conducting means; and

means communicating with said second chamber for siphoning said cooling medium from said second chamber and applying said cooling medium to said surface of said mold liner.

2. In an assembly as in claim 1, the improvement wherein said conducting means comprises an annular web having a plurality of distribution holes therein.

3. In an assembly as in claim 2, the improvement wherein said siphoning means comprises a siphon leg defined by the space between said mold liner and said manifold, with the discharge end of said siphon leg terminating in an annular cooling medium discharge slot, said siphon leg communicating with said second chamber by means of a plurality of siphon ports.

4. In an assembly as in claim I, the improvement wherein said pressure drop across said conducting means is from about 5 to 20 psi.

5. In an assembly as in claim 3, the improvement wherein the distribution holes have a length to diameter ratio greater than 2 to l. v

6. In an assembly as in claim 5, the improvement wherein the pressure drop taken across said siphon ports and said discharge slot is less than 1 psi.

7. In an assembly as in claim 6, the improvement wherein the length to width ratio of said first chamber is greater than 2 to l and the length to width ratio of said second chamber is greater than 3 to l.

8. In an assembly as in claim 7, the improvement wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to I to l and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than 14% to l.

9. In an assembly as in claim 8, the improvement wherein said mold liner comprises a mold portion and a header portion, and said header portion has a polygonal shape.

10. In an assembly as in claim 8, the improvement wherein said cooling medium discharge slot is defined by the gap between an annular lip about the inside periphery of said manifold and a chamfered portion at the discharge end of said mold liner.

11. In an assembly as in claim 9, the improvement wherein said header portion has a pentagonal shape.

12. In an assembly as in claim 10, the improvement wherein said header portion has a hexagonal shape.

13. In an assembly as in claim 9, the improvement wherein a shoulder is provided about the outside periphery of said mold liner at the intersection of said mold portion and said header portion, whereby said mold liner is self-centering within said manifold.

14. In an assembly as in claim 9, the improvement wherein the length of said mold portion is 4% inches or less.

15. In an assembly as in claim 9, the improvement wherein said mold portion has a cylindrical shape.

16. In an assembly as in claim 9, the improvement wherein said mold portion has a noncylindrical shape.

17. A direct chill casting mold manifold for applying acooling medium to a surface of a mold comprising:

a first chamber communicating with a source of cooling medium under pressure; a second chamber, said second chamber having a length to width ratio greater than 3;

means communicating with said second chamber for siphoning said cooling medium from said second chamber, said siphoning means being adapted to apply said cooling medium to said surface of said mold. i

18. A manifold as in claim 17 wherein said second chamber has a length to width ratio of 12 to l.

19. A manifold as in claim 17 wherein said conducting means comprises an annular web having a plurality of distribution holes therein.

20. A manifold as in claim 19 wherein said distribution holes have a length to diameter ratio greater than 2 to l.

21. A manifold as in claim 17 wherein said pressure drop across said conducting means is from about to 20 psi.

22. A manifold as in claim 20 wherein the length to width ratio of said first chamber is greater than 2 to I and the length to width ratio of said second chamber is greater than 3 to 1.

23. A manifold as in claim 22 wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to l to I and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than 1-95 to I.

24. A manifold as in claim 23 wherein an annular lip is provided about the inside periphery of said manifold, said lip being adapted to form with the discharge end of said mold an annular cooling medium discharge slot.

25. In a direct chill casting table having a plurality of mold assemblies therein for casting a plurality of ingots from a single melt, each of said mold assemblies comprising a mold liner and cooling means for applying a cooling medium to a surface of said mold liner, the improvement wherein said cooling means comprises:

a manifold having at least a first and second chamber,

said first chamber communicating with a source of 5 cooling medium under pressure;

means intermediate said first and second chambers for conducting said cooling medium under pressure from said first chamber to second chamber, a substantial pressure drop being taken across said conducting means; and means communicating with said second chamber for siphoning said cooling medium from said second chamber and applying said cooling medium to said surface of said mold liner.

26. In a casting table as in claim 25, the improvement wherein said conducting means comprises an annular web having a plurality of distribution holes therein.

27. In a casting table as in claim 26, the improvement wherein said siphoning means comprises-a siphon leg defined by the space between said mold liner and said manifold, with the discharge end of said siphon leg terminating in an annular cooling medium discharge slot, said siphon leg communicating with said second chamber by means of a plurality of siphon ports.

28. In a casting table as in claim 25, the improvement wherein said pressure drop across said conducting means is from about 5 to 20 psi.

29. In a casting table as in claim 27, the improvement wherein the distribution holes have a length to diameter ratio greater than 2.

30. In a casting table as in claim 29, the improvement wherein the pressure drop taken across said siphon ports and said discharge slot is less than I psi.

31. In a casting table as in claim 30, the improvement wherein the length to width ratio of said first chamber is greater than 2 and the length to width ratio of said second chamber is greater than 3.

32. In a casting table as in claim 31, the improvement wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to l and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than l-r.

33. In a casting table as in claim 32, the improvement wherein said mold liner comprises a mold portion and a header portion, and said header portion has a polygonal shape.

34. In a casting table as in claim 32, the improvement wherein said cooling medium discharge slot .is defined by the gap between an annular lip about the'inside periphery of said manifold and a chamfered portion at the discharge end of said mold liner.

35. In a casting table as in claim 33, the improvement wherein said header portion has a pentagonal shape.

36. In a casting table as in claim 33, the improvement wherein said header portion has a hexagonal shape.

37. In a casting table as in claim 33, the improvement wherein a shoulder is provided about the outside periphery of said mold liner at the intersection of said mold portion and said header portion, whereby said mold liner is self-centering within said manifold.

38. In a casting table as in claim 33, the improvement wherein the length of said mold portion is 4- /5 inches or less.

39. In a casting table as in claim 33, the improvement wherein said mold portion has a cylindrical shape.

40. In a casting table as in claim 33, the improvement wherein said mold portion has a noncylindrical shape. 8 it i

Claims

1. In a direct chill casting mold assembly comprising a mold liner and cooling means for applying a cooling medium to a surface of said mold liner, the improvement wherein said cooling means comprises: a manifold having at least a first and a second chamber, said first chamber communicating with a source of cooling medium under pressure; means intermediate said first and second chambers for conducting said cooling medium under pressure from said first chamber to said second chamber, a substantial pressure drop being taken across said conducting means; and means communicating with said second chamber for siphoning said cooling medium from said second chamber and applying said cooling medium to said surface of said mold liner.

4. In an assembly as in claim 1, the improvement wherein said pressure drop across said conducting means is from about 5 to 20 psi.

5. In an assembly as in claim 3, the improvement wherein the distribution holes have a length to diameter ratio greater than 2 to 1.

7. In an assembly as in claim 6, the improvement wherein the length to width ratio of said first chamber is greater than 2 to 1 and the length to width ratio of said second chamber is greater than 3 to 1.

8. In an assembly as in claim 7, the improvement wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to 1 to 1 and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than 1- 1/2 to 1.

14. In an assembly as in claim 9, the improvement wherein the length of said mold portion is 4- 1/2 inches or less.

17. A direct chill casting mold manifold for applying a cooling medium to a surface of a mold comprising: a first chamber communicating with a source of cooling medium under pressure; a second chamber, said second chamber having a length to width ratio greater than 3; means intermediate said first and second chambers for conducting said cooling medium under pressure from said first chamber to said second chamber, a substantial pressure drop being taken across said conducting means; and means communicating with said second chamber for siphoning said cooling medium from said second chamber, said siphoning means being adapted to apply said cooling medium to said surface of said mold.

18. A manifold as in claim 17 wherein said second chamber has a length to width ratio of 12 to 1.

20. A manifold as in claim 19 wherein said distribution holes have a length to diameter ratio greater than 2 to 1.

21. A manifold as in claim 17 wherein said pressure drop across said conducting means is from about 5 to 20 psi.

22. A manifold as in claim 20 wherein the length to width ratio of said first chamber is greater than 2 to 1 and the length to width ratio of said second chamber is greater than 3 to 1.

23. A manifold as in claim 22 wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to 1 to 1 and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than 1- 1/2 to 1.

25. In a direct chill casting table having a plurality of mold assemblies therein for casting a plurality of ingots from a single melt, each of said mold assemblies comprising a mold liner and cooling means for applying a cooling medium to a surface of said mold liner, the improvement wherein said cooling means comprises: a manifold having at least a first and second chamber, said first chamber communicating with a source of cooling medium under pressure; means intermediate said first and second chambers for conducting said cooling medium under pressure from said first chamber to second chamber, a substantial pressure drop being taken across said conducting means; and means communicating with said second chamber for siphoning said cooling medium from said second chamber and applying said cooling medium to said surface of said mold liner.

27. In a casting table as in claim 26, the improvement wherein said siphoning means comprises a siphon leg defined by the space between said mold liner and said manifold, with the discharge end of said siphon leg terminating in an annular cooling medium discharge slot, said siphon leg communicating with said second chamber by means of a plurality of siphon ports.

30. In a casting table as in claim 29, the improvement wherein the pressure drop taken across said siphon ports and said discharge slot is less than 1 psi.

32. In a casting table as in claim 31, the improvement wherein said source of cooling medium communicates with said first chamber through a cooling medium inlet and wherein the ratio of the length of the first chamber to the diameter of the cooling medium inlet is greater than or equal to 1 and, further, wherein the ratio of the width of the second chamber to the diameter of the distribution holes is greater than 1- 1/2 .

34. In a casting table as in claim 32, the improvement wherein said cooling medium discharge slot is defined by the gap between an annular lip about the inside periphery of said manifold and a chamfered portion at the discharge end of said mold liner.

38. In a casting table as in claim 33, the improvement wherein the length of said mold portion is 4- 1/2 inches or less.

40. In a casting table as in claim 33, the improvement wherein said mold portion has a noncylindrical shape.