US2309036A - Apparatus for conditioning molding sand - Google Patents

Description

Jan. 19, 1943. o. BEARDSLEY APPARATUS FOR CONDITIONING MOLDING SAND Filed Sept. 12, 1940 2 Sheets-Sheet 1 Jan. 19, 1943. E. o. BEARDSLEY' ,3

- APPARATUS FOR CONDiTIONING MOLDING SAND Filed Sept. 12, 1940 2 Sheets-Sheet 2 Patented Jan. 19, 1943 UNITED STATES PATENT OFFICE Elmer 0. Beardsley, Chicago, Ill., assignor to The Beardsley & Piper Company, Chicago, 111., a corporation of Illinois Application September 12, 1940, Serial No. 356,453

17 Claims.

The present invention relates to apparatus for conditioning or treating molding sand, that is, the type of sand which is used in foundries in connection with casting operations.

It is now common foundry practice after a casting operation to remove the packed and heated sand from the flasks and then, in order again to condition it for use in the flasks, to mull it by placing it, together with suitable bonding material, in a receptacle and subjecting it while in the receptacle to the action of rotary mulling elements and plow-like deflectors. The mulling operation serves to break up any lumps in the sand and, in addition, to aerate the sand and mix the bonding material with it. During the mulling operation water is added to the sand in order to moisten it and increase its bonding strength. The amount of water which is added to the sand is critical and hence of extreme importance. If too much water is added to the sand during the mulling operation the permeability of the sand is so reduced that the gases emanating from the molten metal during pouring can not escape through the sand and result in blowing of the sand from the flasks. If too small an amount of water is added to the sand in connection with mulling thereof the sand, when rammed or packed into the flasks, is so dry that it crumbles when contacted by the molten metal and imperfect or unuseable castings result. In most foundries the molding sand is repeatedly used for molding purposes from morning to night. Because of the repeated or successive high temperatures to which the sand is subjected during the day there is a gradual increase of the temperature of the sand and toward the end of the day the sand sometimes is at an extremely high temperature. When the sand is at a high temperature, say 125 F. to 175 F., the water or moisture in the sand evaporates quickly and hence it is practically impossible for the operator of the mulling apparatus so as to control or regulate the introduction of water into the sand during mulling thereof that the sand has the correct or proper moisture content when rammed into the flasks. Another disadvantage or objection to the use of hot sand, that is, sand at a temperature of 25 F. or more above room temperature, is that when the sand is rammed or packed into the flasks the cool or room temperature patterns draw toward them an appreciable amount of moisture from the sand with the result that the sand sticks to the patterns and hence produces rough and undesirable molds or molds which require patching.

The main or primary object of this invention is the provision of an improved sand milling apparatus which contemplates in connection with a sand mulling operation reducing the temperature of the sand to substantially room temperature. By reducing the temperature of the sand to substantially room temperature during mulling of the sand it is possible readily and efficiently to control the moisture content of the sand and also to eliminate sticking of the sand to the patterns. With efiicient moisture control and the elimination of sticking smooth and useable molds are obtained when the sand is rammed into the flasks.

Another object of the invention is to provide a sand mulling apparatus which includes, for sand cooling purposes, means for circulating air under pressure through the sand as the latter is subjected to mulling.

Another object of the invention is to provide a mulling apparatus of the last mentioned type and character which includes in addition to the means for circulating air under pressure through the sand, a dust arrester and suction fan for removing dust and undesirable particles from the sand in connection with a mulling operation.

.A further object of the invention is to provide a sand mulling apparatus which is of the receptacle, rotary mulling element, scraper and plowlike deflector type and includes a rotary screen at the top of the receptaclefor scattering and evenly distributing the sand as it is introduced into the receptacle preparatory to mulling thereof, and also includes means for spraying water onto the sand directly after it passes through the screen and before it enters the receptacle.

A still further object of the invention is to provide a mulling apparatus of the type and character heretofore mentioned in which the means for circulating air under pressure through the sand for cooling purposes and the suction fan for the arrester have control means therefor whereby they may be rendered inoperative.

Other objects of the invention and the various advantages and characteristics of the present sand mulling apparatus will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the 'conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a vertical section showing a sand mulling apparatus embodying the invention, and illustrating the manner in which the air under pressure for sand cooling purposes flows through the sand in suspension and coacts with the dust arrester and suction fan to rid the sand of dust particles;

Figure 2 is a horizontal section taken on the line 2-2 of Figure 1 and disclosing in detail the construction or design of the rotary elements, scrapers and plow-like deflectors of the apparatus; and

Figure 3 is a horizontal section taken on the line 33 of Figure 1 and showing in detail the holes which are formed in the bottom of the receptacle and serve to admit air under pressure into the receptacle for circulation through the sand.

The apparatus which is shown in the drawings constitutes the preferred form or embodiment of the invention. It is expressly designed and adapted for use in a foundry or like establishment and serves as a means for mulling and conditioning molding sand preparatory to use of the latter in flasks. As certain of its parts, the apparatus comprises a bowl-like receptacle 4, a rotary crosshead 5, a pair of rotary mulling elements 6, a pair of scrapers 1, and a pair of plowlike deflectors 8. The apparatus further comprises as parts thereof a blower 9 for circulating air under pressure through the receptacle in connection with mulling of the sand, a dust arrester ID for removing dust particles and fines from the sand, and a suction fan II for drawing the dustladen air into the dust arrester for dust removal purposes. The apparatus is essentially of the batch-type and is designed or adapted to mull and condition successive batches of sand.

The receptacle 4 is adapted in connection with a mulling operation to receive a batch or charge of molding sand for mulling and conditioning purposes, and consists of a flat circular bottom l2 and an annular upstanding side wall I 3. The

receptacle bottom l2, as shown in Figure 1, is of composite design and consists of a fixed inner part [4 and a removable outer part IS. The inner part l4 embodies an integral outwardly extending flange-like structure l6, and this underlies and supports the outer part I5 of the receptacle bottom 2. The receptacle is supported in an elevated position with respect to the floor of the foundry or other establishment in which the apparatus is employed by way of a plurality of legs l1. These legs have, at the upper ends thereof, brackets l8 which are anchored to the flange-like structure l6 of the inner part [4 of the receptacle. The side wall [3 of the receptacle is cylindrical and forms or constitutes a track for the rotary mulling elements 6. The lower marginal portion of the receptacle side wall is formed integrally with the outer marginal portion of the outer part l5. of the receptacle bottom. Clamp bolts l9 extend through slots in the flange-like structure l6 and into the outer part #5 of the bottom and serve removably to hold in place said outer part of the receptacle bottom as well as the side wall l3. In addition to the bottom l2 and the side wall 13 the receptacle comprises a cylindrical shell 25. The lower portion of this shell surrounds the receptacle side wall l3 and is bolted to the flange-like structure I6 of the inner part I 4 of the receptacle bottom. The upper portion of the shell is closed at the top thereof by a circular wall 2| and constitutes a hopper for directing the sand to be mulled into the receptacle. The sand to be mulled may be introduced into the receptacle by any suitable medium such, for example, as an endless belt conveyor 22. The latter as shown in Figure 1 extends horizontally and has the discharge end thereof disposed in an opening 23 in the upper margin of the shell 20. When a batch of sand to be mulled is placed on the upper reach of the conveyor and the conveyor is driven in the proper direction the sand is fed into the top of the shell 20 and then drops downwards into the receptacle 4. Instead of the endless conveyor 22 a, skip hoist, grab bucket or any other suitable charging medium, may be employed to charge the receptacle with successive batches of sand to be mulled or conditioned. A doorway l3 permits the mulled sand to be discharged from the receptacle at the conclusion of a mulling operation. This doorway is normally closed by adoor 13". A fluid pressure operated mechanism I3 (shown in a fragmentary manner in Figure 3) serves to shift the door back and forth between its closed and open positions. When the apparatus is to be used a batch of molding sand is introduced into the receptacle by way of the endless conveyor 22 and then, after being mulled as hereinafter described by the mulling elements 6, is discharged via the doorway l3 due to the action of the deflectors 8.

The crosshead 5 is located in the central portion of the receptacle directly over the bottom [2 and carries and supports the mulling elements, scrapers and deflectors. It is adapted to rotate on a vertically extending axis and embodies a depending drive shaft (not shown). The latter extends through a central hole in the inner part M of the receptacle bottom and is suitably journalled in a housing 24. An electric motor 25 and suitable speed reducing gearing in the housing 24 serve as the medium for rotating the crosshead driving shaft and efiecting drive or rotation of said mulling elements, scrapers and deflectors. The motor 25, as shown in Figure 1, is mounted on a bracket 26 on one of the legs IT. The crosshead 5 embodies at its ends a pair of shafts 21. These shafts extend vertically and fit within and project above and below a pair of tubular sockets 28 at the ends of the crosshead. A horizontal rotary screen 5 is associated with and connected for drive by the crosshead 5. This screen is disposed in the upper end of the shell 20 directly beneath the discharge end of the endless conveyor 22 and operates to scatter and evenly distribute the batch of sand to be mulled immediately before it enters the receptacle 4. A vertically extending shaft 52' connects the screen for drive by the crosshead and this shaft has its upper end journalled in a bearing 5 on the circular wall 2|. A bracket 5 extends between the lower end of the shaft 5* and the upper ends of the shafts 21.

The mulling elements 6 are disposed in the upper portion of the receptacle 4 and are in the form of wheels. They preferably consist of cast metal bodies and solid rubber tires and are carried by a pair of horizontally extending arms 29 so that they are permitted to swing outwards towards the receptacle side wall. The arms 29 are disposed above the crosshead 5 and beneath the bracket 5 and project away from the ends of the latter. The inner ends of the arms have sleeve-like members 30 and these are rotatably mounted on the upper ends of the shafts 21. The shafts 2'! and the sleeve-like members 30 serve as connections between the arms and the crosshead whereby the arms, together with the wheel-type mulling elements 6 are caused to travel around the receptacle and at the same time are permitted to swing outwards in response to centrifugal force, during drive of the crosshead. The elements 6 extend horizontally and are adapted, in connection with drive of the crosshead, to travel around the receptacle side wall and in addition to spin and effect mulling of the sand by squeezing it against the side wall. They are rotatably mounted on vertically extending shafts at the distal ends of the arms 29. Chains 3| between the distal ends of the arms 29 and the upper ends of the shafts 21 serve to limit or restrict outward movement of the mulling elements 6. During drive of the crosshead by the motor 25 the mulling elements swing outwards toward the receptacle side wall and, as hereinbefore pointed out, are caused in response to the action of the arms 29 to travel in a circular course around the side wall. As the elements engage the sand around the inner periphery of the receptacle side wall, they squeeze it and in this manner mull it and effect an even or uniform distribution of any bonding material therein. Because the outward movement of the mulling elements is limited the tires of the elements are kept from striking the doorway in connection with discharge of the sand after mulling.

The scrapers 1 are adapted to scrape the mulled sand from the receptacle side wall and direct it inwards. They are disposed in the upper portion of the receptacle 4, as shown in Figure l, and are located directly behind the wheel-type mulling elements 6. The upper ends of the shafts 21 have the scrapers fixedly secured thereto and serve as a medium for causing the scrapers to rotate around the receptacle side wall in connection with drive of the crosshead.

The plow-type deflectors 8 are fixed to, and extend outwardly from, the lower ends of the shafts 21 and are positioned behind the scrapers 1. During operation of the apparatus the deflectors 8 serve to deflect the sand upwards and outwards against the upper portion of the inner periphery of the receptacle side wall and into the path of the mulling elements. The del flectors are canted, as illustrated in the drawings, and coact with the scrapers to maintain the sand in suspension in the receptacle during drive of the crosshead. When the apparatus is in operation with a batch of sand in the receptacle, the sand is first squeezed against the side wall by the mulling elements, then is scraped inwards in the direction of the deflectors and then is thrown outwards and upwards against the side wall and into the path of the following element and this occurs twice each revolution of the crosshead. The arrangement of the operating "parts is such that the entire mass of sand in the receptacle is maintained in suspension. The scrapers and deflectors in scraping and deflecting the sand so scatter the grains of sand that the sand is effectively aerated. The crosshead is preferably driven at such a speed that the scrapers travel at the rate of approximately 1350 feet per minute because at such speed the deflectors and scrapers operate to maintain the sand in suspension in the receptacle. When the door l3 is opened at the end of a mulling operation the deflectors 3 serve to discharge the mulled sand through the doorway l3.

The blower 9 serves as a means for circulating air through the sand in the receptacle for cooling purposes. It coacts with the dust arrester and the suction fan H to eliminate dust from the sand during a mulling operation and consists of a blade-equipped rotor 32 and a casing 33. The casing 33 is mounted on a frame 34 on the foundry floor and embodies an inlet 35 and a tubular discharge duct 36. A plate valve 35 is associated with the inlet 35 and permits the operator of the apparatus to regulate to any desir'eddegree or completely out off the flow of air through the receptacle. When the valve is closed substantially no air under pressure enters the receptacle even though the rotor of the blower is revolving. The outlet end of the discharge duct is disposed beneath the receptacle 4 of the apparatus and is connected to a ring-shaped manifold 31 on the bottom of the inner part 14 of the receptacle bottom l2. Such manifold is formed as an integral part of said inner part l4.

and communicates with the interior of the receptacle by way of an annular series of holes 38. These holes, as shown in Figures 1 and 3, extend through the inner part I4 of the receptacle bottom wall and are located inwardly of the deflectors 8. Instead of an annular series of holes an annular slot may be employed to introduce the air under pressure into the bottom portion of the receptcle 4. The blade-equipped rotor 32 is disposed in the casing 33 and is adapted to be driven at a constantspeed by an electric motor (not shown). When the blower motor is in operation and the inlet 35 of the blower casing is either partially or fully open the rotor 32 operates to draw outside air into the casing via the inlet. Such air is placed under pressure and is forced through the outlet duct 36 into the manifold 31. From the manifold the air under pressure flows upwards through the holes 38 into the interior of the receptacle. A ring-shaped baffleplate 39 is carried by the lower ends of the shafts 21 and operates to deflect the air under pressure so that after entering the receptacle it flows outwards across the outer part of the receptacle bottom and then upwards through the sand in suspension. As the air under pressure passes upwards through the sand it serves not only to cool the grains of sand but also to aerate the sand. From the receptacle the air under pressure passes upwards into the upper portion of the cylindrical shell 26. A ring-shaped rib 40 is connected to and projects upwardly from the inner part Id of the receptacle bottom and underlies the ring-shaped baflle plate 39. This rib is disposed outwardly of the annular series of holes 38 and prevents any sand on the receptacle bottom from passing to the holes 36. It is contemplated that the blower 9 will be in operation before a batch of sand is introduced into the receptacle. As has heretofore been indicated, the sand is generally at a comparatively high temperature before it enters the receptacle and this is due to contact with the molten metal. By cooling the sand as it is mulled it is possible accurately to control or regulate the moisture content of the sand and also to prevent the sand from sticking or adhering to the patterns.

The dust arrester If is located adjacent the upper portion of the cylindrical shell 26. It embodies a housing 4! and suitable or conventional dust arresting elements (not shown) in the housing M. The housing is suitably supported on a bracket 42 and embodies an air inlet duct 43 and an air outlet duct 44. The inlet duct 43 extends between the upper portion of the housing 4| and the upper margin of the cylindrical shell 25. It effects communication between the shell interior and the housing interior and has a valve 43 for controlling the flow of air into the dust arrester Ill. The outlet duct 44 is located at the bottom or lower end of the housing 4|, as shown in Figure 1. The suction fan H is associated with the outlet duct 44 and when in operation or efiective serves to draw air from the interior of the shell through the duct 43 and into the housing 4|. It is of the centrifugal type and includes a casing 45 and a blade-equipped rotor 45. The casing has an air inlet in communication with the outlet duct 44 and embodies a discharge duct 47. The fan is adapted to be constantly driven during use of the apparatus. In the event that the valve 43 is closed no air from the receptacle flows into the dust arrester housing although however a vacuum is built up within the housing. Such vacuum results in an immediate inflow of air into the housing when the valve 43 is opened. When air with dust or fines is drawn into the housing 4! of the dust arrester ID the dust arresting elements in the housing serve to filter out and remove the particles and fines prior to egress of the air from the housing. When a batch of sand is delivered into the receptacle and the valves and 43 are either fully or partially opened the dust particles and fines in the sand are directed upwards by the air under pressure flowing upwards through the receptacle and are drawn into the housing 4| where, as previously described, they are removed from the air.

In addition to the previously described parts or elements, the apparatus comprises a pipe 48 for introducing water into the sand in connection with a mulling operation. This pipe is disposed eXteriorly of the receptacle 4 and is adapted to receive water under pressure from any suitable source of supply. It is preferably located adjacent the blower 9 and terminates as far as the discharge end thereof is concerned, in two branch pipes and 50. The branch pipe 49 extends upwardly along the outside of the shell 20 and is connected to a ring-shaped spray 5 which is located in the upper portion of the shell directly beneath the rotary screen 5*. The spray pipe embodies downwardly and inwardly extending spray nozzles 52 and is adapted when water under pressure is permitted to flow into it through the branch pipe 49, to jet streams of water downwardly and inwardly onto the sand in the receptacle. A valve 53 is included in the branch pipe 49 so as to regulate the fiow of water th'erethrough. The branch pipe is arranged so that the discharge end thereof extends through the outer part l5 of the receptacle bottom i2. It is adapted to supply a portion of water from the main water pipe 48 directly into the receptacle and includes a valve 54 for regulating the flow of water under pressure therethrough. The main pipe 48 includes a flow meter 55 so that the operator of the apparatus may ascertain the amount of water introduced into the sand. A main control valve 56 is connected to the water pipe 48 between the flow meter 55 and the branch pipes 49 and 5B. When this valve is closed no water flows into the two branch pipes. Usually the valves 53 and 54 are set so that a part of the water which is introduced into the sand for moistening purposes flows through the spray pipe and the remainder into the bottom of the receptacle via the branch 50. With the valves 53 and 54 set in this manner opening of the main valve 56 results in. introduction of water into the sand. The water which is introduced into the receptacle via the branch pipe 50 flows over the bottom wall of the receptacle and is mixed with the grains of sand due to the action of the plowlike deflectors 8. When the sand in the receptacle is moistened and air under pressure is circulated through it quick cooling of the sand takes place due to evaporation of a part of the moisture.

The apparatus may be operated in either of two different ways or manners. Firstly, it may be operated so as to effect mulling and cooling of the sand and also removal of the dust and fines in the sand. Secondly, it may be operated in such manner that the desired mulling and cooling of the sand are effected without any removal of the fines. When the first mentioned mode of operation is practiced the motor 25, the blower 9 and the suction fan H are first started. As soon as current is supplied to the motor 25 the mulling elements, scrapers and plow-like deflectors are caused to swing or travel in a circular course around the inner face of the side wall l3 of the receptacle. Before the sand to be mulled is introduced into the receptacle the valves 35 and 43 are partially closed. After this operation the sand to be mulled is introduced into the upper end of the shell 20 by way of the endless conveyor 22. It is contemplated that the sand to be mulled be removed from the flasks immediately after use thereof and while it is in a heated condition due to contact with the molten metal. As soon as the sand enters the shell it is scattered by way of the rotary screen 5. As the sand descends or drops into the receptacle in a scattered condition the air under pressure from the blower 9 elevates the dust and fines and brings them within the vicinity of the duct 43. As soon as the dust and fines reach such vicinity they are drawn into the housing 4! of the dust arrester I5 in response to the action of the suction fan H. As previously pointed out, the dust and fines are removed from the air during passage of the air through the housing 4|. After introduction of the sand into the receptacle the valve 55 in the main pipe line 48 is opened until the desired amount of water is discharged into the receptacle via the branch pipe 50 and the spray pipe 5|. As soon as the desired amount of water has been introduced into the sand the valve 55 is closed. The sand, after entry into the receptacle, is subjected to the action of the mulling elements 6, the scrapers 7 and the plow type deflectors 8. Immediately after moistening of the sand the valves 35 and 43 are fully opened. As soon as these valves are opened to their fullest extent rapid cooling of the sand takes place because of the up-fiow of air under pressure through the moist sand while the latter is in suspension in the receptacle. Cooling of the sand results from the up-flow of air in the receptacle and evaporation of a part of the water or moisture in the sand. At the start of the mulling operation the valves 35 and 43 cannot be fully opened because some of the molding sand would be drawn into the dust arrester and lost. It is contemplated that the operator of the apparatus will set the valves so that during entry of the sand into the receptacle only the dust and fines of a particular size will be eliminated. When the valves 35 and 43 are fully opened after the sand has been moistened no sand is lost because the sand is heavy due to its moistening. The elements 6 during drive on the crosshead serve to squeeze the sand against the receptacle side wall and thus mull it and the scrapers and deflectors operate, as hereinbefore described, to maintain the sand in suspension over the receptacle bottom and position it for mulling by the mulling elements. At the conclusion of the mulling operation the door I3 is opened by manipulation of the mechanism 13. As soon as the door is swung into its open position the plow-like deflectors 8 fling the mulled and cooled sand out of the receptacle via the doorway l3 When it is desired to operate the apparatus in such manner as to remove no fines in the sand the motor 25, the blower 9 and the suction fan I l are first set into operation. Thereafter the valves 35 and l? are fully closed. With these valves in their fully closed position no air under pressure circulates upwardly through the receptacle and shell. As soon as the valves are closed the sand to be mulled is introduced into the upper end of the shell by way of the endless conveyor 22. As the sand is being scattered by the screen the valve 56 is opened and this results in moistening of the sand. When the proper or desired amount of water has been introduced and the sand is hence in such a condition that air under pressure will not disturb the fines in the sand the valves 35 and #3 are opened. Upon opening of these valves the blower operates to flow upwards through the sand in the receptacle a constant stream of air under pressure and such air cools the sand. The suction fan H assists the blower in efiecting a rapid circulation of air through the receptacle and shell. It is contemplated that the blower and suction fan be of such capacity that the air which is circulated by them in connection with operation of the apparatus will reduce the sand to room temperature during the course of its mulling period. The suction fan I l prevents a positive pressure within the receptacle and shell and this is of importance since such a pressure might result in sand being forced or blown through the sand inlet opening 23. By having the valve 33 in the inlet duct 43 as distinguished from the discharge duct 41 suction is built up in the housing 4! of the dust arrester prior to opening of the said valve in connection with a mulling operation. With suction in the housing there is immediate up-flow of air through the sand and cooling of the latter immediately takes place when the valves 35 and 53 are opened by the operator.

The herein described apparatus is comparatively simple as far as design and construction are concerned and is characterized by the fact that it includes means for cooling the sand during the mulling operation as well as means for optionally removing dust and fines from the sand. By bringing the sand to room temperature during the mulling operation materially greater efliciency in foundry practice is effected. Furthermore it is possible accurately to control the moisture content of the sand and also to eliminate any likelihood of the mulled sand sticking to the patterns because of temperature difierence.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

The sand conditioning method which is carried out in connection with operation of the present apparatus is covered by, and forms the subject matter of, United States Letters Patent No.

- 1y used molding 2,264,610, granted to applicant on December 2, 1941, on an application filed as a division of this application for Letters Patent.

Having thus describedthe invention, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for conditioning hot previously used molding sand, comprising a bowl-shaped receptacle for holding a batch of sand to be conditioned, means for repeatedly and alternately pressure squeezing the sand against the receptacle side wall without pulverizing it and scattering the sand while at the same time maintaining substantially the entire batch in suspension in the receptacle, embodying a rotary power driven crosshead in the receptacle, a mulling element carried by the crosshead adjacent to and spaced from said receptacle side wall, and a plow type deflector supported by said crosshead in front of the element, and means associated with the receptacle for circulating air under pressure through the sand while it is scattered and in suspension in said receptacle in order to cool it.

2. An apparatus for conditioning hot previoussand, comprising a bowl-shaped receptacle for holding a batch of the sand to be conditioned, means for repeatedly and alternately pressure squeezing the sand against the side wall of the receptacle without pulverizing it and scattering the sand while at the same time maintaining substantially the entire batch in suspension in the receptacle, embodying a rotary power driven crosshead in the receptacle, a mulling element carried by the crosshead adjacent to and spaced from said receptacle side wall,

and a plow type deflector supported by said crosshead in front of the element, and a motor operated blower adjacent the receptacle operative to force air under pressure and at atmospheric temperature through the scattered and A suspended sand in the receptacle for cooling purposes, and having the inlet thereof open to the atmosphere surrounding the receptacle and its outlet connected to the receptacle interior.

3. An apparatus for conditioning hot previously used molding sand, comprising a bowl-shaped receptacle for holding a batch of sand to be conditioned, means for repeatedly and alternately pressure squeezing the sand against the side wall of the receptacle without pulverizing it, and

scattering the sand while at the same time maintaining substantially the entire batch in suspension in the receptacle, embodying a rotary power driven crosshead in the receptacle, a mulling element carried by the crosshead adjacent to and spaced from said receptacle side wall, and a plow type deflector supported by said crosshead in front of the element, and a power operated blower independent and out-side of the receptacle operative to force air under'pressure and at atmospheric temperature upwards through the scattered and suspended sand for cooling purposes, and having a valve controlled inlet open to the atmosphere surrounding the receptacle and an outlet connected to, and in communication with, the bottom of the receptacle.

4. An apparatus for conditioning hot previous-- ly used molding sand, comprising a substantially closed receptacle for the sand, means for repeatedly and alternately pressure squeezing the sand against the receptacle side wall without pulverizing it, and scattering the sand in the receptacle while at the same time maintaining substantially the entire batch in suspension, ernbodying a rotary power driven crosshead in the receptacle, a mulling element carried by the crosshead adjacent .to and spaced from said receptacle side wall, and a plow type deflector supported by said crosshead in front of the element, and means for circulating air under pressure and at atmospheric temperature upwardly through the scattered and suspended sand in the receptacle for cooling purposes consisting of a power operated blower disposed adjacent and outside of the receptacle and having the inlet thereof open to the surrounding atmosphere and its outlet connected to the bottom of the receptacle and a power operated suction fan disposed exteriorly of the receptacle and having the inlet thereof connected to the top of the receptacle and its outlet open to the surrounding atmosphere.

5. An apparatus for conditioning hot previously used molding sand, comprising a receptacle for the sand, means for repeatedly and alternately pressure squeezing the sand, against one wall of the receptacle without pulverizing it, and scattering the sand, embodying a rotary power driven crosshead in the receptacle, a rotary mulling element adjacent to and spaced from said one wall and connected for drive by the crosshead, and a plow type deflector supported by said crosshead in front of the element, means for delivering water into the receptacle in order to moisten the sand therein, and means for circulating air under pressure past the scattered sand in the receptacle in order to cool it.

6. An apparatus for conditioning molding sand, comprising a substantially closed receptacle for the sand, means for mulling the sand in the receptable by pressure squeezing it against one wall of the receptacle without pulverizing it, and scattering the sand, embodying a rotary power driven crosshead in the receptacle, a rotary mulling element adjacent to and spaced from said one wall of the receptacle and connected for drive by the crosshead, and a plow type deflector supported by said crosshead in front of the element, a dust arrester disposed exteriorly of the receptacle and having a valve controlled inlet connected to the top of the receptacle, and means for circulating air under pressure so that it travels upwards through the scattered sand and then into the dust arrester consisting of a power driven blower disposed eX- teriorly of the receptacle and having a valve controlled inlet open to the surrounding atmosphere and its outlet connected to, and communicating with, the bottom of the receptacle, and a power driven suction fan connected to the air discharge of the dust arrester.

7. An apparatus for conditioning molding sand, comprising a substantially closed receptacle for the sand, means for repeatedly and alternately mulling the sand in the receptacle by pressure squeezing it against one wall of said receptacle without pulverizing it, and scattering the sand, embodying a rotary power driven crosshead in the receptacle, a rotary mulling element disposed adjacent to, and spaced from, said one wall of the receptacle and connected for drive by the crosshead, and a plow type deflector supported by said crosshead in front of the element, a dust arrester connected to the top of the receptacle, and means for circulating air under pressure upwardly through the scattered sand in the receptacle and then into and through the dust arrester consisting of a power driven blower disposed exteriorly of the receptacle and having a valve controlled inlet open to atmosthe receptacle for pressure squeezing phere and in addition having the outlet thereof connected to the receptacle bottom, and a power driven suction fan connected to the air discharge of the dust arrester.

8. An apparatus for conditioning hot previously used molding sand, comprising a bowl-like receptacle having an opening at the top thereof and adapted to have a batch of the sand to be dumped into it through said opening, rotary power operated means in the receptacle for mulling the sand by pressure squeezing it against one wall of the receptacle without pulverizing it, means for circulating air under pressure past the sand during mulling thereof in order to cool it, means at the top of the receptacle for spraying Water onto the sand as it is dumped into the receptacle, and means independent of the spray means for introducing water onto the bottom of the receptacle.

9. An apparatus for mulling molding sand, comprising a receptacle adapted to have the sand introduced into it from above, rotary power driven means in the receptacle for mulling the sand without pulverizing it, a screen adjacent the top of the receptacle and connected for con joint drive with said means for scattering the sand during introduction thereof into the re ceptacle, and means beneath the screen for spraying water into the receptacle and onto the sand.

10. An apparatus for conditioning hot previously used molding sand, comprising a receptacle adapted to have the sand introduced into it from above, rotary power driven means in the receptacle for mulling the sand without pulverizing it, a screen adjacent the top of the receptacle and connected for conjoint drive with said means for scattering the sand during introduction thereof into the receptacle, means beneath the screen for spraying water into the receptacle and onto the sand, and means for circulating air under pressure past the sand during mulling thereof for cooling purposes.

11. An apparatus for conditioning molding sand, comprising a substantially closed receptacle for the sand, power driven means in the receptacle for pressure squeezing the sand against one Wall of the receptacle in order to mull it without pulverization, a dust arrester connected to the receptacle, means for circulating air under pressure so that it travels past the sand in the receptacle and thence into and through the dust arrester, and valve controlled means for delivering water into the receptacle for sand moistening purposes.

12. An apparatus for conditioning molding sand, comprising a substantially closed receptacle for the sand, power driven means in the re ceptacle for pressure squeezing the sand against one wall of the receptacle in order to mull it without pulverization, a dust arrester connected to the receptacle, means including a power driven blower connected to the receptacle and a power driven suction fan connected to the air discharge end of the dust arrester for circulating air under pressure past the sand in the receptacle and thence into and through the dust arrester, and valve controlled means for delivering water into the receptacle for sand moistening purposes.

13. An apparatus for conditioning viously used molding sand, comprising tacle for the sand, power driven rotary hot prea recepmeans in the sand against one wallv of the receptacle in order to mull it without substantial pulverizatio'n, means [or flowing air under pressure and at atmospheric temperature upwards past the sand during mulling thereof, and valve controlled means adjacent the top of the receptacle for delivering water onto the sand in the receptacle.

14. An apparatus for conditioning hot previously used molding sand, comprising a receptacle for the sand, means for repeatedly and alternately pressure squeezing the sand against one wall of the receptable without pulverizing and scattering the sand while at the same time maintaining substantially the entire batch of sand in suspension in the receptacle, embodying a rotary power driven cros-shead, a rotary mulling element carried by the crosshead adjacent to and spaced from said one wall of the receptacle, and a plow type deflector supported by the crosshead in front of the element, a power driven blower connected to the receptacle bottom for circulating air under pressure upwards through the sand while it is in suspension in the receptacle, and valve controlled means for delivering water into said receptacle for sand moistening purposes.

lb. An apparatus for conditioning hot pre' viously used molding sand, comprising a receptacle for the sand, power driven rotary means in the receptacle for pressure squeezing the sand against one wall of the receptacle in order to mull it without substantial pulverization of the sand grains, means for delivering water into the receptacle for sand moistening purposes, and means for circulating air through the receptacle and past the sand in order to cool .the latter.

16. An apparatus for conditioning hot previously used molding sand, comprising a receptacle for the sand, power driven rotary means in the receptacle for pressure squeezing the sand against one wall of the receptacle in order to mull it without pulverizing the sand grains, means for delivering water into the receptacle for sand moistening purposes, and a power operated blower independent and outside of the receptacle operative to force air under pressure and at atmospheric temperature past the sand for cooling purposes and having a valve controlled inlet open to the atmosphere surrounding the receptacle and its outlet in communication with the receptacle interior.

1'7. An apparatus for conditioning hot previously used molding sand, comprising a receptacle for the sand, power driven rotary means in the receptacle for pressure squeezing the sand against one wall of the receptacle in order to mull it Without substantial pulveriza'tion of .the grains, means for delivering water into the receptacle for sand moistening purposes, and a motor driven suction fan connected to the receptacle by way of a duct with a valve therein and operative when driven and while the valve is open to draw air through the receptacle and past the sand for sand cooling purposes.

ELMER O. BEARDSLEY.

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