US2592340A

US2592340A - Apparatus for the preheating of pattern plates

Info

Publication number: US2592340A
Application number: US40874A
Authority: US
Inventors: Ronceray Robert Andre
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-01-20
Filing date: 1948-07-27
Publication date: 1952-04-08
Anticipated expiration: 1969-04-08

Description

April 8, 1952 R. A. RONCERAY APPARATUS FOR THE PREHEATING OF PATTERN PLATES Filed July 27, 1948 6 Sheets-Sheet l IVA VA llllul llllllllll W" "n HJHHHHHHH -"HPHHHH INYENTOR ROBE-RT A. ROA CERAY ATTORNEYS April 8, 1952 R. A. RONCERAY APPARATUS FOR THE PREHEATING OF PATTERN PLATES Filed July 27, i948 6 Sheets-Sheet 2 INVEN TOR ROBERT A.- RONCERAY ATTORNL'YS April 8, 1952 R. A. RONCERAY APPARATUS FOR THE PREHEATING OF PATTERN PLATES 6 Sheets-Sheet 3 9 Filed July 27, 1948 M OW a w W 4 H M.

INVENTOR ROBERT A. RO/VCERAY By My m ATTORNEYS 6 Sheets-Sheet 4 ATTORNE Y5 April 8, 1952 R. A. RONCERAY APPARATUS FOR THE PREHEATING OF PATTERN PLATES Fig.9

April 8, 1952 R. A. RONCERAY 2,592,340

APPARATUS FOR THE PREHEATING OF PATTERN PLATES Filed July 27, 1948 6 Sheets-Sheet 5 ROBER TIM/AYTOQQOHCERAY y ATTORNEYS April 8, 1952 R. A. RONCERAY 2,592,340

APPARATUS FOR THE FREE-[EATING OF PATTERN PLATES Filed July 27, 1948 s Sheets-Sheet e ROBERT A. RONCERAY y M ATTO NEYJ Patented Apr. 8, 1952 APPARATUS FOR THE PREHEATING OF PATTERN PLATES Robert Andr Ronceray, Thiais, France Application J uly 27, 1948, Serial No. 40,874 In France January 20, 1948* 2 Claims.

The present invention relates to a method for pre-heating the pattern-plates used in foundry work for moulding.

It has also for its object a device which permits of preheating these plates, and finally it comprises the pattern-plates fitted with this device or adapted for the application of this method.

There exists, in foundry work, a considerable disadvantage caused by the cold in winter. It is known that the metal pattern-plates utilized are at a low temperature, and the casting sand, slightly moist, clings to the plates when in contact with them. This adherence causes sand to be ripped off in the course of the pattern removal, rendering the mould useless.

It has thus been necessary to pre-heat the pattern-plates, and, in order to do this, several more or less empirical means have been utilized.

These means consist namely, eitherin pre-heating the plate itself by exposing it before a source of heat, or in pro-heating the molding table of the molding machine, for instance by means of an electric resistor located within its thickness. But these methods present many drawbacks. In the last mentioned method, namely, a considerable time must elapse before the pattern-plate is heated, because the warming up first involves heating the whole mass of the table and, moreover, the pattern-plate may have a very considerable thickness. These methods are namely inadequate when moving frequently from place to place; On the other hand, the heating elements do not stand up well under the repeated jars to which they are submitted on the machine.

It is the object of thepresent inventionto provide a method which will remedy these drawbacks and which insures an effective and controlled pre-heating under all conditions.

The method according to the inven ion consists substantially in causing to flow in, or in contact with the pattern-plate, a hot or previously heated fluid.

The fluid used is composed; preferably, but not exclusively, of compressed air, since the casting machines are either actuated by compressed air or fitted with a blower functioning by means of air under pressure.

The device according to the invention comprises, substantially, the combination, with a moulding or casting machine, of a preheating device for the fluid used, of a heat exchanging device in contact with or within the pattern-plate to be pre-heated, and of means for slowing down the expansion of the heating fluid at its exit from the device, in order to prevent it from expanding, and to avoid, consequently, a lowering of its temperature.

It will be understood that, while remaining within the scope of the invention, it is possible to omit the particular pre-heating device if one can obtain a hot fluid which can be drained, at least in part, in order to utilize it according to the invention.

Keeping the foregoing inmind, compressed air is utilized by preference as pre-heating fluid, the latter being conducted to the heating device by a suitable conduit taken on the compressed air circuit of the machine. The heat exchanger is advantageously formed by a very good heat-conducting metal tube and which is located either in a groove or slot machined on the lower surface of the pattern-plate, in the case of a single pattern-plate, or sunk in the. mass of the patternplate during its manufacture, when the patternplate is a double surface plate or when this pattern-plate has a considerable thickness.

In one form of embodiment of the invention which can more especially be applied to single surface pattern-plates, the heat exchanger is simply constituted by a cast groove or out, which is closed by a plate positioned between the pattern-plate and the table of the machine, so that this groove may form a conduit, in conjunction with this plate. The latter could, moreover, be made integral with the pattern-plate.

In any case, this groove, and the metal tube, are given a sinuous shape, so as to insure an equal and. fast distribution of the heat in the pattern-plate.

It will be noted that the replacingof a patternplate can be carried out almost as fast as when a pattern-plate of the usual type is utilized, since it is only necessary to disconnect and re-connect a conduit, flexible by preference, conducting the hot fluid to the pattern-plate according to the invention.

The pre-heating device is advantageously formedv by a heat-insulated container, within which is arranged a heating. system and through which passes a compressed air flow partly expanding in said container.

It is an advantage to provide deflectors in this container, in order that the flowing air follows a path as long as possible around this heating organ; and thus makes a maximum utilization of the heatvalue.

The mentioned heating device may also be connected to the heat-exchanger, for instance by means of flexible tubes.

The heating device may be equipped so that it can receive either a hot fluid such as steam, or an electric resistor either encased or not, single or multiple.

In the latter case, it is advantageous to use a two part resistor, or a resistor receiving two different voltages so as to obtain relatively strong pre-heating at the start when using a given type of pattern-plate, and to obtain a working temperature capable of maintaining the pre-heated pattern-plate at the desired temperature.

When the heating device is an electric resistor, it should be in operation, only when the heating fluid flows around it, so as to avoid overheating, which would cause possible damage.

According to the invention, a device actuated by the pressure of the flowing fluid. is'provided,

controlling the opening or the closing oithe electrical circuit. This device may be in the form of a push-member receiving on one face the action of the said fluid, and actuating either a mercury- "rocking contact breaker, or a switch.

The following specification, together with the appended drawings, given as non-limitative examples, describe the invention and the characteristics which stand out from the text, as well as from the drawings, being understood'as included in the invention.

, Fig. 1 shows a plan view of a pattern-plate according to the invention, seen from the bottom;

Fig. 2 shows a cross-sectional view through IIII of Fig. 1;

' Fig. 3 shows a plan view of a double patternplate according to the invention;

. Fig.. 4' shows a cross-sectional 'IVIV of Fig. 3

Fig. 5 shows a vertical cross-sectional viewof one form of embodiment of an air-heater;

Fig. 6 shows a vertical cross-sectional view of a modification;

Fig. 7 shows a longitudinal cross-sectional view of another modification;

Fig. 8 shows a cross-sectional view through 'VIII-VIII of Fig. 7;

Fig. 9 shows a longitudinal cross-section of another form of embodiment of a pre-heater;

, Figs. .10 and 11 illustrate schematically the arrangement of a pre-heater on a moulding machine;

Fig. 12 shows a partly elevational cross-sectional view of one form of embodiment comprising an automatic safety device. v

Figs. 1 and 2 illustrate one form of embodirnent of a pattern-plate according-totheinvention. This pattern-plate is constituted by a supporting 'plate I on which the pattern proper 2 is secured.

According to the invention, this plate bears a groove or slot 3, formed or milled therein according to whether the pattern-plate already exists or if it is a plate which will becast according to the invention.

A simple slot can be made which will, later, be closed on its free surface, by an asbestos plate positioned between the supporting plate {I and the table of the moulding machine This asbestos plate, not shown, plays simultaneously the part of the fourth side of the conduit 3 and of thermal insulator between the pattern plate and the table of the machine, thus preventing heat losses through the latter by heating. In this case, an intake nozzle 4 is fixed at one end of the conduit 3 at the other end of which an air flow retarding device 5 is provided. This air flow retarding device prevents the hot fiuid from expanding in the conduit 3 and consequently avoids a loss of heat of this fluid.

View through It is also possible, in thisform of embodiment, to more simply mill the conduit 3 and arrange in this conduit a metal tube 6, made of copper for instance, as illustrated partly in Fig. 1. In this case the milled or moulded conduit 3 could be filled with asbestos, in order to avoid heat losses; it is also possible to utilize the asbestos plate mentioned in the preceding paragraph. The nozzle 4 is connected by means of an air-tight flexible tube to the exit nozzle of the fluid pre-heater.

In the case illustrated in Figs. 3 and 4 Where a double surface pattern-plate is used, this pattern-plate is provided with a supporting plate 1, on which the members 8 and 9 of the pattern proper are secured. In this case, it is more advantageous to provide, during the moulding of the pattern-plate, a heating circuit constituted bya metal tube It, made of good heat-conducting material, copper for example, which is arranged in the mould, so as to be sunk in the plate in the moulding process. This tube is also fitted with an intake nozzle II and an air valve 12 at the exit, similar to those which have been dcscribed concerning'Figs. 1 and 2.

In all cases, the path followed by the heating agent is made as sinuous as possible, so as to insure a heat distribution as fast and as even as possible.

As it has been mentioned above, it is practical to use, as heating fluid, the compressed air of which a constant use is made in moulding machines. The said compressed air may be preheated in various manners, but it has proved to be particularly advantageous to utilize a heating system constituted by an electric resistonsince this system can be used in all cases.

In the form of embodiment of a pre-heater illustrated in Fig. 5, this pre-heater is provided by a tube l3, covered with an insulating compound M and which is closed at its two ends by plugs 15 and I6 respectively, which are, for example, screwed on the tube I. In this tube, an

electric resistor H, in the shape of a hairpin and of a known model is arranged. It can, for example, be constituted by -a ferro-nickel wire coated and insulated and placed within a small metal tube.

A simple U shaped arrangement has been 11- lustrated, but, as it will be understood, any similar arrangement may be considered, for example: double U, sinusoid, etc. This resistor is fixed on the lower plug l5 and bears two binding posts for the-electriccurrent. This plug comprises also an intake nozzle 20 connected to the compressed air conduit of the machine, and it is provided with a calibrated opening 2! for limiting the air intake speed which enters within the tube l3 and which expands in this tube. This air flows around the resistor I1, is heated and flows out through the nozzle 22 of the plug l6, this nozzle having preferably greater dimensions than the intake nozzle 20. This nozzle will be connected :to, the intake nozzle, such as 4 or H, of the pattern-plate by a flexible conduit.

In the form of embodiment illustrated in Fig. 6, the air heater proper comprises also a tube 23, covered with an insulating covering 24 and which is also closed at its ends by

plugs

25 and 26.

In this form of embodiment, the electric resistor is wound on an insulating core 21 of any suitable shape. This core is fixed in the plug 25, for example by means of nuts and bolts 28, 29. A binding post 30, for the electric current is provided in the plug 25, and the wire which has been wound on the core 21 issues outside through the axial conduit 3! provided in this core, inorder to end on the binding post 32 provided at the endofthe said core.

The compressed air is admitted in the inner chamber 33 through the nozzle 34 fitted also with acalibrated opening 35. Deflecti'ng partitionsas in 36, 31, etc. force-the air to follow the long path around the resistor before flowing out through the nozzle 38 mounted on the opposite plug 26.

It. is to be understood that the constitution of the core- 21' can be-of any shape: plug, tube, plate or'evena simple frame.

In the form of embodiment shown in Figs. 7 and 8, the electrical resistor 39, formed for example in the same manner asthe resistor ll of Fig; 5, is sunk in a tubular mass 40, for instance made of'aluminium in the case where-the resistor 39 itself is insulated. This mass 40 ends in a ring 4| and bears in and

outbinding posts

42, 43 for the electric current. The resistor thus formed is enclosed in a box 44, preferably coated with a coating of thermal insulating material 45. This box is closed by the ring 4| which bears against it and is retained by a plate 49 and a plate 41 positioned therebetween made of insulatingv material.

The

plates

46 and 41 bear, naturally, drilled openings to pass the

binding posts

42, 43. The whole assembly may be enclosed in a metal envelope 41a.

The tubular mass 40 comprises a plurality of drilled radial openings as shown in 48, 49. The compressed air is admitted through the nozzle 50 which passes through the bottom of the box and is provided with a calibrated opening 5!. This air flows thus all along the resistor in the annular chamber 52 or inside the tubular mass 40, and flows out through the tube 53 which. issues almost level with the openings 48 and is extended by the exit nozzle 54. In this. manner, the air is in contact with the resistor for a considerable length oi'time.

This pre-heating device can be mounted on a plate 55 for its attachment to the moulding machine.

In the embodiment shown in Fig. 9, the heating resistor 56 is also wound in spiral form and sunk in an aluminium mass 51, this resistor being of the insulated type and placed within a metal tube. This mass 51 is equipped with blades 58 forming a continuous spiral. The overall shape is frustro-conical corresponding to a similar shape of the box 59, this insuring a sealing between these blades and this box. The air introduced through the nozzle 60 fitted with a callbrated opening 6| flows thus in spirals between these blades, around the mass 51. Then it passes through this mass through conduits as shown in 52, 63, 64, drilled at a place located the furthest from the intake nozzle and enters the central conduit 65 drilled in the mass 51, which issues outside where it reaches the exit nozzle 65.

In this embodiment also, the box 59 is coated with a layer of thermal insulating material 67, and the mass 5'! ends in a circular plate 68 which engages frictionally in the free opening of the box 59. The two ends of the resistor which pass through this plate end externally at the binding posts 69 and for connection to the electric current.

The assembly is made by means of the upper threaded end of the tube 65 on which the nozzle 66 is screwed, as shown at H. A metal Washer 12 presses on the lining 51 and consequently on the bottom. of the box, completing the" assembly and insuring the tightnessthereof.

Thus'the' electric resistor maybe replaced simply by unscrewing thenozzle 66 and removing. the wirefrom thebinding posts. On the other hand, the calibrated part BI is located in aplug- 13 screwed in the intake nozzle 60, and is'thus easily accessible, and can be cleaned with great facility.

Fig. 10 illustrates a moulding machine '14 on which is mounted a pattern-plate 15 formed as described in relation with Figs. 1. to 4.

The nozzle 4 or II of this plate 15 is connected through a flexible tube: 16 to the air pro-heater 71 which is fixed. on the column 18 of the ma chine, the. intake nozzle of' this pro-heater beingconnected by the tube'l9 to the compressed. air source. The pattern-plate is shown: here in the moulding position.

In the form of embodiment shown in Fig. 1 1, the air pre-heater. is here fastened: to the column and is connected, in the manner described relating to Fig. 10, to the pattern-plate 6|, which in this case isa single surface plate. This plate. 8| is insulated from. the slab 83 0f the machine by an asbestosplate 82'.

Whichever form of embodiment of electric preheater is used, it is important that. the electric current be switched oif from the resistor when the heated fluid does not flow, for any reason, and to switch it on again only when the fluid has resumed its flow.

Fig. 12 shows a vertical cross-section of a device which automatically insures the opening and the closing of the electrical heating circuit. and is actuated by the pressure of the-fluid con ducting heat tothe pattern-plates. This device adapts itself, without any changes being made, to any one of the pr'e-heating organs described above.

The admission of compressed air into the heating chamber is made through the feeding' block 34, screwed on the lower part-85 of the heating resistor support. The air enters through the nozzle 86 screwed in the block 84, passes then into the transverse conduit 8! to the conduit 88 which issues into the heat chamber, passing through the calibrated opening 89.

In the conduit 8?, a chamber 90 issues which is closed by a piston 9| the rod of which 92, protrudes outward from the block 84 and is urged toward the nozzle 89 by a spring 93.

The electric switch is here a mercury circuit breaker 94, the cradle of which is connected at to a bracket 97 integral with the block 84. This cradle is pressed at its end 98, on the rod 92 by a spring 99 bearing on the support 85 of the resistor.

One of the supply wires I00, goes straight to one of the binding posts of the resistor, while the circuit breaker is inserted in the second wire I0l.

In the example shown the air intake is interrupted and theh electric circuit is open. When 3 the compressed air is let in, it pushes back the piston 9| against the springs 93 nd 99. The circuit breaker then rocks and the electric circuit is closed whereupon the resistor heats. If a new interruption occurs in the compressed air flow, the pressure in the conduit 81 decreases, the piston and the circuit breaker are brought back to the position shown and the electric circuit is again open.

The above described assembly is advantageously protected by a jacket I02 extending towards the bottom from the metal washer I03 which, by

7 screwing onto the end 85 of the resistor support, closes the heat chamber.

The devices which have been described above therefore insure an individual pre-heating for each machine of the air utilized for the heating of the pattern-plate and thus insuring a great adaptability in the operation of the moulding installation.

The forms of embodiments hereinabove described are given as non-limitative examples, and modifications of details may be made without departing from the scope of the invention.

The air pre-heater, namely, could be of any type difierent from those hereinabove described, as long as it insures the pre-heating of the com pressed air on each machine.

" What I claim is:

1. An apparatus for the pre=heating of patternplates mounted on a moulding machine for the construction of sand moulds used in foundry work, which comprises, in combination with a moulding machine driven by compressed air and a pattern-plate, a conduit connected to said machine for receiving compressed air therefrom, an electric device for the pre-heating of the compressed air, a heat insulated container within which is arranged said electric device and connectedto said conduit, an inlet and an outlet for the compressed air provided in said container and calibrated so as to permit an expansion of the compressed air in it, a heat exchange device disposed in the pattern-plate to be pro-heated, a further conduit connecting said heat exchange device to the outlet of said container, control means connected to said first mentioned conduit for receiving and being actuated by the compressed air therein and an electrical switch connected to the circuit of said electrical device for controlling the source of current thereto and to said control means for being actuated thereby and closing said circuit upon the passage of compressed air through said first mentioned conduit.

2. An apparatus for the pre-heating of patternplates mounted on a moulding machine for the construction of sand moulds used in foundry work, which comprises, in combinationwith a moulding machine driven by compressed air, and a pattern plate, a conduit connected to said machine for receiving compressed air therefrom, an electric device for the pre-heating of the compressed air, a heat insulated container within which is arranged said electrical device, an inlet connected to said conduit and an outlet for the compressed air provided in said container and calibrated so as to permit an expansion of the compressed air in it, a heat-exchange device disposed in the pattern-plate to be pre-l'ieated a further conduit connecting said heat-exchanging device to the outlet of said container, a cylinder connected to said first conduit for receiving compressed air therefrom, a piston slidably mounted in said cylinder, resilient means positioned against said piston and in said cylinder, and a mercury switch connected to said electrical device for controlling the supply of current thereto and to said piston for being closed upon passage of compressed air and normally opened by said spring.

ROBERT ANDRE RONCERAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Germany Apr. 16, 1912