US2344363A - Method and apparatus for cooling metal molds - Google Patents

Description

Man-ch 14, 1944. H. E. MCWANE METHOD AND APPARATUS FOR COOLINGMETAL MOLDS Filed Jan. 3, 1942 2 Sheets-Sheet l WMM@ @@MJ@ Patented Mar. 14, 1944 UNITED STATES-PATENT OFFICE METHOD AND APPARATUS FOR COOLING METAL MOLDS The present invention relates to casting, and more particularly it has reference to a method and apparatus for cooling metal molds so that the danger of the cooling media entering the casting cavity is minimized.

Of course, means have heretofore been provided ior cooling permanent metal molds, but, to the best of my knowledge, the cooling media or water has always been admitted intl the water jacket under pressure. While this type of cooling is generally satisfactory, it does present one problem which has always caused difiiculty in the industry. As is well known, metal molds often develop small cracks lor fissures which extend into the casting cavity. Consequently, when the water in the jacket is under pressure, there is a real danger that the water will be admitted into the casting cavity in the event the crack is of suilicient size, thereby causing an explosion not only damaging the mold but also proving hazardous to the foundryrnen.

Anobject of the present invention is to provide a method and apparatus for cooling permanent metal molds wherein the cooling media is circulated throughout the water jacket under negative pressure.

Another object of the present invention is to provide a novel cooling system for permanent molds wherein the cooling media is not circulated in the jacket at elevated pressures.

And avfurther object of the present invention is to provide means for supplying cooling media to a water jacket at such pressures as will pren vent the water or cooling media entering the casting cavity.

To accomplish the above and other important objects, the invention in general `comprises connecting the water jacket with a source of cooling media in such a manner that thel water is drawn from'the source of supply intoA the water jacket and thence back to the source of supply.

More specifically, a pump is provided on suction side of the mold wherebythe water circulating through the water jacket will be kept at a negative `pressure, thus eliminating the,I l

danger of the water entering the mold cavity through any small cracks or fissures which be present in the mold body.

In the drawings in which like numeralsindicate the same or similar parts:

Figure 1 is a diagrammatic representation ci of supply andthe casting machine for circu-.

lating the cooling media in the water jackets of the mold parts.

Figure 2 is a transverse sectional view taken along the line 2-2 of Figure 1 looking in the.

direction of the arrows.

Figure 3 is a transverse sectional view taken along the line 3-3 of Figure 1 looking in the direction of the arrows.

In Figure 1 there is shown a supply tank I for water or some other suitable cooling medium. The tank I is mounted above the oor of the foundry upon a support 2 and is in communication with water jackets 3 and 4 of xed and movable mold parts 5 and 6, respectively, by means of a system of pipes or conduits designated generally 1. The fixed and movable mold parts are supported upon a casting frameindicated 8, and the construction'and operation of the casting frame and its associated parts are shown and described in my copending application Serial No. 413,214, filed October 1, 1941, now Patent 2,313,253, dated March 9, 1943.

As best shownin Figure 1, an inlet pipe 9 has interposed therein a valve Ill for controlling the flow of water into the tank l from a watermain (not shown). An outlet II located adjacent to the bottom wall of the tank I is provided with a control valve I2 and conduit I3 is suitably coupled to the valve I2. The conduit I3 extends below the surface of the foundry floor or the like, and a main inlet conduit Ill is attached to the lower end of the conduit I3 as shown at I5. Secured to the main conduit I4 by a T-connection I B is a lateral conduit I "I, Coupled to the pipe I'I is a Vertical conduit I3 which termihates above the floor of the foundryadjacent to the frame 8. A flexible conduit I9 is at.- tached to the upper end of the conduit I8, as shown at 20, and the opposite end thereof. is in communication with the water jacket 3 of the :fixed mold ypart v5. A second flexible conduit 2! extends from the water jacket 3 to the upper end of a vertical conduit 22 which is secured by a T-connection 23 toa lateral pipeZ. The pipe 2A ig'conveniently coupled at 25V to a main return` pipe 2d which is parallel to the .pipe I4. A vertical section of pipe 21 is coupled to the end ofv the main return conduit or pipe 25 and the upper end of the conduit 21 is suitably con vnected to a suction pump 28 mounted on the support 2. The pump 28 is adapted to be driven by an electric motor 29 through a connection 39.

Conduit 3i is secured at its lower end to the pressure side of the pump 28, and attached to the ,upper end thereof as shown at 32 is a spray pipe` 33 that is disposed within the tank I adjacent to the upper end thereof. An overflow aperture 34 provided adjacent to the upper end of the tank has connected thereto an overflow pipe 35 which is attached by a T-connection 36 to a conduit 31 that leads to a suitable drain which is not shown. The pipe 31 has provi-ded therein a control valve 38 which is connected to the conduit I4 in any desirable manner. A similar control valve 39 is also connected to the pipe I4 and to the pipe or return conduit 28. The purpose of these valves will later be more fully described.

To cool the movable mold part 6 I provide an arrangement which is similar to that for coolilur the xed mold part and the corresponding elements bear the same numerals with the exception that they are primed. It should be mentioned that my invention is generally employed in connection with a series of casting frames 8, and the mold parts of each frame are connected to the tank I in the same manner as the frame 8 just described.

While the operation of my system is believed to be readily apparent from the above description, it may be briefly summarized as follows. When the requisite amount of cooling medium, suill- Vcient only to completely fill the water jackets of all the molds employed in the above-mentioned series has been admitted into the tank I through the inlet conduit 9, the valve I is manipulated to arrest the flow of the water. 'I'he suction pump 28, of course, is driven through the motor 29 and water is drawn from the tank I through the conduit I3 past the open valve I2 into the main pipe or conduit I4. `Of course, the control valves 38 and 39, provided in the conduit 31 which leads to the drain, are closed to prevent the water from by-passing into the drain. The water is drawn from the main conduit I4 through the lateral conduits I'I and I1 into the vertical pipes I8 and I8 through flexible conduits I9 and I9 into the water jackets 3 and 4 to cool the mold parts and 6, respectively. The water circulates through the jackets and is drawn out through the flexible connections 2 I and 2 I into the vertical pipes 22 and ,22' and into the lateral conduits 24 and 24'. From the lateral conduits 24 and 24 the water enters the main return conduit 26 and is drawn into the pump 28 and is discharged through the vertical pipe 3| and into the spray pipe 33. The water leaving the spray pipe 33, of course, is cooled bycondensatio-n.

In the event it is desired to drain the water from the system, the valves 38 and 39 are actuated to permit the conduits I4 and 26 to communicate with the conduit 31 and the operation thereof is thought to be readily apparent.

It should be mentioned that when the whole system is lled with the cooling medium, the co1- umn of liquid in the tank I is balanced by that in the water jackets ofthe molds and consequently the Water in they/ater jackets will not be u nder pressure and when the suction pum-p 28 is operating the pressure in the jackets will be re duced below atmospheric. This is particularly important in that there is no danger of the water entering the casting cavity through any cracks or the like which may be present in the mold parts. Hence the danger of an explosion occurring within the casting cavity is reduced materially.

The apparatus by which I control the cooling of then-letal mold parts is simple in construction and in operation and can be manufactured at a relatively low cost. The inlet and outlet yconduits below the floor level of the foundry and the advantages of this feature are thought to be clear. Furthermore, in the event of injury to any of the equipment, it is possible to repair or replace the equipment in a minimum of time.

While I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set forth by way of illustration, as it is apparent that many changes and variations may be made therein, by

Ythose skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. A method of cooling water jacketed metal molds comprising introducing a cooling liquid from an open reservoir thereof into the water jacket wherein the hydrostatic head of the liquid in the jacket is equal substantially to the hydrostatic head of liquid in the reservoir, and withdrawing liquid from the jacket by suction to reduce the pressure in the rjacket to a pressure below atmospheric.

2. A method of cooling water jacketed metal molds comprising introducing a cooling liquid from an open reservoir thereof into the water jacket wherein the hydrostatic head of the liquid in the jacket is equal substantially to the hydrostatic head of liquid in the reservoir, withdrawing liquid from the jacket by suction to reduce the pressure in the jacket to a pressure below atmospheric, and returning the withdrawn liquid to the said reservoir.

3. A method of cooling Water jacketed metal molds comprising introducing a cooling liquid from an open reservoir thereof into the water jacket wherein the hydrostatic head of the liquid in the jacket is equal substantially to the hydrostatic head of liquid in the reservoir, withdrawing liquid from the jacket by suction to reduce the pressure in the jacket to a pressure below atmospheric, cooling the withdrawn liquid, and returning the withdrawn liquid to the said reservoir.

4. A method of cooling water jacketed metal molds comprising introducing a cooling liquid from an open reservoir thereof into the water jacket wherein the hydrostatic head of the liquid in the jacket is equal substantially to the hydrostatic head of liquid in the reservoir, withdrawing liquid from the jacket by suction to reduce the pressure in the jacket to a pressure below atmospheric, and spraying the withdrawn liquid into said reservoir in contact with the air to effect a cooling of the returned liquid.

5. In an apparatus for cooling metal molds having a water jacket, a tank containing a cooling liquid, conduit means connecting the tank with the water jacket for supplying liquid from the tank to said jacket, an overflow pipe communicating with the tank for controlling the amount of liquid therein whereby the hydrostatic head of the liquid in the jacket when filled balances substantially the hydrostatic head of liquid in the tank, additional conduit means connecting leading from the tank to the casting machine are 7'a the jacket with the tank, and a suction pump associated with the last named conduit means for withdrawing liquid from the jacket and discharging it into the tank to establish thereby a circu lation of liquid in the jacket at a pressure below atmospheric.

6. In an apparatusfor cooling metal molds having a water jacket, a tank containing a cooling liquid, conduit means connecting the tank with the Water jacket for supplying liquid from the tank to said jacket, an overow pipe communicating with the tank for controlling the amount of liquid therein whereby the hydrostatic head of the liquid in the jacket when filled balances substantially the hydrostatic head of liquid in the tank, a suction pump, a conduit connecting the jacket With the input side of said pump, a second conduit having a connection with the discharge side of the pump and communicating with the tank in a region above the liquid level therein, said pump adapted to withdraw liquid from the jacket and discharge it to the tank to establish thereby a circulation of liquid in the jacket at a pressure below atmospheric, and a plurality of orices in the last named conduit for discharging the liquid into the tank in the form of a spray.

HENRY E. MCWANE.

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