US3568755A - Machine for the manufacture of articles of a slurry of solid matter in a liquid - Google Patents

Machine for the manufacture of articles of a slurry of solid matter in a liquid Download PDF

Info

Publication number
US3568755A
US3568755A US732652A US3568755DA US3568755A US 3568755 A US3568755 A US 3568755A US 732652 A US732652 A US 732652A US 3568755D A US3568755D A US 3568755DA US 3568755 A US3568755 A US 3568755A
Authority
US
United States
Prior art keywords
mould
slurry
improvement
air
vessel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US732652A
Inventor
Daniel Fredrik Ednell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Foseco Trading AG
Original Assignee
Foseco Trading AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Foseco Trading AG filed Critical Foseco Trading AG
Application granted granted Critical
Publication of US3568755A publication Critical patent/US3568755A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00Casting ingots, e.g. from ferrous metals
    • B22D7/06Ingot moulds or their manufacture
    • B22D7/10Hot tops therefor
    • B22D7/108Devices for making or fixing hot tops
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28BSHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00Producing shaped prefabricated articles from the material
    • B28B1/26Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
    • B28B1/268Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor by dipping moulding surfaces in the slip

Definitions

  • Parker ABSTRACT A machine for manufacture of articles by deposition of solid matter in a slurry on a perforated mould, a pressure difference being established for forcing the liquid component through the said pressure difference being reversed to blow off the deposited article, the blowing means being located outside the means for depositing the solid matter.
  • the present invention is related to a machine for the manufacture of articles by deposition of solid matter in a slurry on a hollow perforated mould, which, while it is submerged in the slurry, is subjected to a pressure difference so that the slurry liquid will be drained through the mould, while the solid matter is deposited on one side of the mould, the deposited article being releasable from the mould by means of an opposite pressure difference.
  • the articles which may be manufactured on machines of this type can have various uses, but the machines are particularly adapted to manufacture of refractory details arid components for moulds for casting metal. These components are manufactured by various manufacturers and the articles are delivered to foundries. The components which are most in demand are usually in store ready to be dispatched as required. For larger foundries with continuous casting of metal it is very important "that the foundry is continuously and evenly supplied with the refractory components as it would be too costly to have all that is needed in store. For this reason larger foundries have started to manufacture the refractory components for, the casting moulds, and this manufacture will then have to be in step with the other casting operations.
  • the object of the present invention is therefore primarily to provide a machine of the kind in question, having good reliability and also possibilities of being included in existing plants, the machine being able to work at high speeds.
  • the problem is solved by blowing the article from the mould by an air blast. Due to the air blast the deposited article will expand slightly so that it will not be retained in the perforations of the mould, and when the work is continuous it is of advantage to let the deposited article when it is blown off pass directly to the casting mould the article is to be combined with. Due to this short transport of the articles the possiblity of damaging the articles is substantially reduced.
  • the machine according to the invention is consequently mainly characterized in that it comprises a blow device located outside the slurry vessel and movable for cooperation with the mould when the mould is brought under the blow device, as lowering of the blow device controls valves admitting air under pressure to the mould so that the deposited article is loosened from same.
  • a preferred embodiment of the invention is characterized in that the blow device is in the form of an air cylinder which at one end is closed by a ball valve, the ball of which being releasable by an abutment when the cylinder is lowered on the the mould, whereby the supply of air under pressure to the interior of the mould is established.
  • the mould is, in accordance with the invention, provided with a one-way valve at the bottom, the valve body of said valve opening when abutting a projection in the slurry vessel for-draining of liquid, while the valve closes the mould when the deposited article is to be blown off.
  • FIG. 1 is a section through a slurry vessel with the mould in place ready for deposition of solid matter to form the article;
  • FIG. 2 is a section through another part of the machine in accordance with the invention.
  • FIG. 3 is a view corresponding to FIG. 2 when the deposited article is blown off.
  • the machine comprises a slurry vessel which, by means of automatic equipment, is filled with a slurry to the level indicated at 2.
  • a level indicator 3 controls a valve 4 to keep the level of the slurry constant.
  • the vessel 1 is divided into two chambers 5 and 6 by means of a partition 7 which is open at the lower end as indicated at 8.
  • a perforated mould 9 is located and on the mould the solids of the slurry are to be deposited.
  • Air under pressure is supplied at an inletll) by means of a valve 11.
  • the air enters the outer chamber 6 and drives the slurry up through the opening 8 and into the chamber 5.
  • the slurry occupies the space around the mould 9 and the slurry liquid is forced through the mould by the air under pressure.
  • the slurry-liquid is drained away through the outlet 12.
  • a valve 13 is in an interconnection 14 between the two chambers 5 and 6 is opened to equalize the pressure in these chambers. The remaining part of the slurry in the chamber 5 will then flow down into the chamber 6, and as long as the vales ll and 13 are open the air under pressure will provide further draining of liquid in the deposited article.
  • the mould 9 is attached to a rotatable disc which is indicated only diagrammatically at 18, and this disc is raised and carries the mould 9 with the deposited article so that the mould 9 is brought under a blow device which is shown in FIG. 2.
  • the blow device comprises an air cylinder 19 which may be raised and lowered, for example pneumatically, and it has an air inlet at 20 near the upper end, while the lower end is closed by a ball valve 21.
  • a projection 22 above the mould will lift the ball 21, as shown on FIG. 3, so that the air can enter the interior of the mould 9.
  • the mould 9 In order to blow off the deposited article 24 the mould 9 must be closed, and the valve 16 which is open in FIG. 1, is in FIGS.
  • Packing devices 23 which fit closely around the lower end of the cylinder 19 when the cylinder 19 is in its lower position are shown in FlGS. 2 and 3.
  • the mould 9 is in the example shown suspended in chains 25 and it may be lowered together with the air cylinder 19, as shown in FIG. 3. By suspending the mould 9 in chains 25 or in another movable manner the positioning of the components to which the article 24 is to be transferred, is no longer critical.
  • the present invention has provided a very simple, sturdy and reliable construction of a machine for continuous manufacture of the articles in question under difficult conditions, and the embodiment described shall not be considered as a limitation of the protection offered by this patent as other embodiments are possible within the scope of the invention, the valves for example may be designed in other manners and the mould may be suspended in other elements than the chains shown. Control means, automatic regulators etc. which form no part of the invention, are not included in this specification.
  • Improvement in a machine for manufacturing articles by deposition of slurry comprising a hollow perforated mould, a slurry vessel adapted to receive the mould, means for removing the mould from the slurry vessel, a blowing device in the form of a vertically movable air cylinder closed at one end by a ball valve for supplying air under pressure to the interior of the mould to loosen a deposited article from the mould, and abutment means contacting and releasing the ball of said ball valve when the cylinder is in a position lowered towards the mould to establish a supply of air to the interior of the mould.
  • Improvement as claimed in claim 1 including packing devices which fit closely to the end of the cylinder when the cylinder is in the lower position.
  • the slurry vessel is divided into two chambers by wall means, each of said chambers having means for supplying air under pressure with interconnections for supply of air under pressure to one chamber, the other chamber or both chambers, a supply of air to one chamber being efiective to drive slurry up round the mould and a supply of air to the other chamber being effective to drive slurry away from the mould, and to drive air through the mould and the deposited matter.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Producing Shaped Articles From Materials (AREA)
  • Devices For Post-Treatments, Processing, Supply, Discharge, And Other Processes (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)

Abstract

A machine for manufacture of articles by deposition of solid matter in a slurry on a perforated mould, a pressure difference being established for forcing the liquid component through the said pressure difference being reversed to blow off the deposited article, the blowing means being located outside the means for depositing the solid matter.

Description

United States Patent Daniel Fredrik Eduell Ed, Sweden May 28, 1968 Mar. 9, 1971 Foseco Trading A.G. Chur, Switzerland July 3, 1967 Norway Inventor Appl. No. Filed Patented Assignee Priority MACHINE FOR THE MANUFACTURE OF ARTICLES OF A SLURRY OF SOLID MATTER IN A 166,156, 213, 306, 23, 24, 25, 26, 180, 181; 25/Porous Mold digest; 18/2 (RA), 5 (BR), 16 (F); 264/86, 87, 335; 210/4 11 [56] References Cited UNITED STATES PATENTS 2,290,083 7/1942 Webster 164/156 2,356,013 8/1944 Spooner-...... 164/156 3,022,540 2/1962 Shapero 18/24 3,183,292 5/1965 Dvoracek 264/335 3,379,804 4/1968 Loosjes et al. 264/87 3,380,509 4/1968 Hentrich et al. 164/306 3,439,734 4/1969 Eastwood 164/33X 3,414,471 12/1968 l-Iochart 264/87X Primary Examiner-J. Spencer Overholser Assistant Examiner-John E. Roethel Attorney-Albert M. Parker ABSTRACT: A machine for manufacture of articles by deposition of solid matter in a slurry on a perforated mould, a pressure difference being established for forcing the liquid component through the said pressure difference being reversed to blow off the deposited article, the blowing means being located outside the means for depositing the solid matter.
JJ I l:
I i 4 Z, 45 ii I 4 2 t1:
PATENTED my 91971 SHEET 1 UF 2 FINVENTOR. DAN/EL FREDR/K LCDNELL ATTORNEX PATENTED MAR 9 |97| SHEET 2 0P2 INVENTOR. DAN/El. FREDR/K [DA ELL ATTORNE).
. MAQHIINE FOR THE MANUFAGTURE h ARTICLES OF A SHERRY 0F SOLID MATTER IN A LIQUID The present invention is related to a machine for the manufacture of articles by deposition of solid matter in a slurry on a hollow perforated mould, which, while it is submerged in the slurry, is subjected to a pressure difference so that the slurry liquid will be drained through the mould, while the solid matter is deposited on one side of the mould, the deposited article being releasable from the mould by means of an opposite pressure difference.
The articles which may be manufactured on machines of this type can have various uses, but the machines are particularly adapted to manufacture of refractory details arid components for moulds for casting metal. These components are manufactured by various manufacturers and the articles are delivered to foundries. The components which are most in demand are usually in store ready to be dispatched as required. For larger foundries with continuous casting of metal it is very important "that the foundry is continuously and evenly supplied with the refractory components as it would be too costly to have all that is needed in store. For this reason larger foundries have started to manufacture the refractory components for, the casting moulds, and this manufacture will then have to be in step with the other casting operations. A breakdown of the machine on which the refractory components are made, will however, resultin serious interruptions of long duration in the operation of the foundry, and it is imperative that the machine for the manufacture of the articles in question be so sturdy and reliable that it will not fail even under the difficult working conditions prevailing in a foundry.
The object of the present invention is therefore primarily to provide a machine of the kind in question, having good reliability and also possibilities of being included in existing plants, the machine being able to work at high speeds.
The main problems in this connection are due to the removal of the deposited article on the mould which, even if water has been drained away, still has a high moisture content and is pliable.
in accordance with the invention the problem is solved by blowing the article from the mould by an air blast. Due to the air blast the deposited article will expand slightly so that it will not be retained in the perforations of the mould, and when the work is continuous it is of advantage to let the deposited article when it is blown off pass directly to the casting mould the article is to be combined with. Due to this short transport of the articles the possiblity of damaging the articles is substantially reduced.
The machine according to the invention is consequently mainly characterized in that it comprises a blow device located outside the slurry vessel and movable for cooperation with the mould when the mould is brought under the blow device, as lowering of the blow device controls valves admitting air under pressure to the mould so that the deposited article is loosened from same.
A preferred embodiment of the invention is characterized in that the blow device is in the form of an air cylinder which at one end is closed by a ball valve, the ball of which being releasable by an abutment when the cylinder is lowered on the the mould, whereby the supply of air under pressure to the interior of the mould is established.
A condition to be observed when the deposited at article is to be blown off from the mould is that the mould must be closed in order to prevent air from escaping without expanding the deposited article, while it is a condition for proper deposition of the slurry that the mould is provided with openings through which the slurry liquid passing through the mould may drain away. In order to solve the problems these two conditions involve, the mould is, in accordance with the invention, provided with a one-way valve at the bottom, the valve body of said valve opening when abutting a projection in the slurry vessel for-draining of liquid, while the valve closes the mould when the deposited article is to be blown off.
Other characteristic features and details of the invention will be evident from the following description with reference to the drawings on which:
FIG. 1 is a section through a slurry vessel with the mould in place ready for deposition of solid matter to form the article;
FIG. 2 is a section through another part of the machine in accordance with the invention; and
FIG. 3 is a view corresponding to FIG. 2 when the deposited article is blown off.
As shown on FIG. 1 the machine comprises a slurry vessel which, by means of automatic equipment, is filled with a slurry to the level indicated at 2. A level indicator 3 controls a valve 4 to keep the level of the slurry constant.
The vessel 1 is divided into two chambers 5 and 6 by means of a partition 7 which is open at the lower end as indicated at 8. In the chamber 5 a perforated mould 9 is located and on the mould the solids of the slurry are to be deposited. Air under pressure is supplied at an inletll) by means of a valve 11. The air enters the outer chamber 6 and drives the slurry up through the opening 8 and into the chamber 5. In this chamber the slurry occupies the space around the mould 9 and the slurry liquid is forced through the mould by the air under pressure. The slurry-liquid is drained away through the outlet 12. When a sufiicient quantity of solid matter has been deposited on the mould 9 in order to give the article the desired thickness, a valve 13 is in an interconnection 14 between the two chambers 5 and 6 is opened to equalize the pressure in these chambers. The remaining part of the slurry in the chamber 5 will then flow down into the chamber 6, and as long as the vales ll and 13 are open the air under pressure will provide further draining of liquid in the deposited article.
At the bottom of the mould 9 in the exemplary embodiment shown in the drawing, there a one way valve 16 is provided, which, when the mould 9 is in place in the chamber 5, is held open by a projection 17, and the purpose of this valve will be described more in detail.
The mould 9 is attached to a rotatable disc which is indicated only diagrammatically at 18, and this disc is raised and carries the mould 9 with the deposited article so that the mould 9 is brought under a blow device which is shown in FIG. 2. The blow device comprises an air cylinder 19 which may be raised and lowered, for example pneumatically, and it has an air inlet at 20 near the upper end, while the lower end is closed by a ball valve 21. When the air cylinder 19 is lowered, a projection 22 above the mould will lift the ball 21, as shown on FIG. 3, so that the air can enter the interior of the mould 9. In order to blow off the deposited article 24 the mould 9 must be closed, and the valve 16 which is open in FIG. 1, is in FIGS. 2 and 3 in closing position, so that the air pressure in the mould 9 will act on the article 24 to expand same, and the article will then fall from the mould 9. Packing devices 23 which fit closely around the lower end of the cylinder 19 when the cylinder 19 is in its lower position are shown in FlGS. 2 and 3.
The mould 9 is in the example shown suspended in chains 25 and it may be lowered together with the air cylinder 19, as shown in FIG. 3. By suspending the mould 9 in chains 25 or in another movable manner the positioning of the components to which the article 24 is to be transferred, is no longer critical.
The present invention has provided a very simple, sturdy and reliable construction of a machine for continuous manufacture of the articles in question under difficult conditions, and the embodiment described shall not be considered as a limitation of the protection offered by this patent as other embodiments are possible within the scope of the invention, the valves for example may be designed in other manners and the mould may be suspended in other elements than the chains shown. Control means, automatic regulators etc. which form no part of the invention, are not included in this specification.
I claim:
1. Improvement in a machine for manufacturing articles by deposition of slurry comprising a hollow perforated mould, a slurry vessel adapted to receive the mould, means for removing the mould from the slurry vessel, a blowing device in the form of a vertically movable air cylinder closed at one end by a ball valve for supplying air under pressure to the interior of the mould to loosen a deposited article from the mould, and abutment means contacting and releasing the ball of said ball valve when the cylinder is in a position lowered towards the mould to establish a supply of air to the interior of the mould.
2. Improvement as claimed in claim 1, including packing devices which fit closely to the end of the cylinder when the cylinder is in the lower position.
3. Improvement as claimed in claim 1, characterized in that the bottom of the mould is equipped with a one-way valve, the valve member of which opening by abutment against a projection in the slurry vessel, in order to drain away the slurry liquid.
4. Improvement as claimed in claim 1 wherein the slurry vessel, with the mould in place therein, is closed and is adapted to be subjected to pressure for depositing a predetermined quantity of solid matter from the slurry and for draining away the slurry liquid from the deposited solid matter.
5. Improvement as claimed in claim 4, wherein the slurry vessel is divided into two chambers by wall means, each of said chambers having means for supplying air under pressure with interconnections for supply of air under pressure to one chamber, the other chamber or both chambers, a supply of air to one chamber being efiective to drive slurry up round the mould and a supply of air to the other chamber being effective to drive slurry away from the mould, and to drive air through the mould and the deposited matter.
6. Improvement as claimed in claim 4, characterized in that the vessel is provided with a level regulator for controlling the supply of slurry to the vessel.
7. Improvement as claimed in claim 1, including means for movably suspending the mould during blowing off of the.
deposited article.
8. Improvement as claimed in claim 1, including means for movably suspending the air cylinder during the blowing off of the deposited article.

Claims (7)

  1. 2. Improvement as claimed in claim 1, including packing devices which fit closely to the end of the cylinder when the cylinder is in the lower position.
  2. 3. Improvement as claimed in claim 1, characterized in that the bottom of the mould is equipped with a one-way valve, the valve member of which opening by abutment against a projection in the slurry vessel, in order to drain away the slurry liquid.
  3. 4. Improvement as claimed in claim 1 wherein the slurry vessel, with the mould in place therein, is closed and is adapted to be subjected to pressure for depositing a predetermined quantity of solid matter from the slurry and for draining away the slurry liquid from the deposited solid matter.
  4. 5. Improvement as claimed in claim 4, wherein the slurry vessel is divided into two chambers by wall means, each of said chambers having means for supplying air under pressure with interconnections for supply of air under pressure to one chamber, the other chamber or both chambers, a supply of air to one chamber being effective to drive slurry up round the mould and a supply of air to the other chamber being effective to drive slurry away from the mould, and to drive air through the mould and the deposited matter.
  5. 6. Improvement as claimed in claim 4, characterized in that the vessel is provided with a level regulator for controlling the supply of slurry to the vessel.
  6. 7. Improvement as claimed in claim 1, including means for movably suspending the mould during blowing off of the deposited article.
  7. 8. Improvement as claimed in claim 1, including means for movably suspending the air cylinder during the blowing off of the deposited article.
US732652A 1967-07-03 1968-05-28 Machine for the manufacture of articles of a slurry of solid matter in a liquid Expired - Lifetime US3568755A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NO168914A NO120851B (en) 1967-07-03 1967-07-03

Publications (1)

Publication Number Publication Date
US3568755A true US3568755A (en) 1971-03-09

Family

ID=19910135

Family Applications (1)

Application Number Title Priority Date Filing Date
US732652A Expired - Lifetime US3568755A (en) 1967-07-03 1968-05-28 Machine for the manufacture of articles of a slurry of solid matter in a liquid

Country Status (3)

Country Link
US (1) US3568755A (en)
GB (1) GB1212566A (en)
NO (1) NO120851B (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2290083A (en) * 1940-06-04 1942-07-14 William R Webster Continuous molding machine
US2356013A (en) * 1943-08-03 1944-08-15 Rossi Irving Continuous casting of metals
US3022540A (en) * 1953-10-06 1962-02-27 Continental Can Co Dipping apparatus for fabricating flexible containers
US3183292A (en) * 1962-05-25 1965-05-11 Dvoracek Frank Plastic molding apparatus and method
US3379804A (en) * 1964-06-10 1968-04-23 Konink Sphinx Ceramique V H Pe Method of the production of a body from a slip in a porous mold
US3380509A (en) * 1964-08-17 1968-04-30 Suedwestfalen Ag Stahlwerke Method of pressure treatment of metallic melts, especially steel melts
US3414471A (en) * 1964-03-26 1968-12-03 Henry Boucher Fils & Cie Pulp molding apparatus
US3439734A (en) * 1965-12-06 1969-04-22 Foseco Trading Ag Apparatus for forming hot top liners

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2290083A (en) * 1940-06-04 1942-07-14 William R Webster Continuous molding machine
US2356013A (en) * 1943-08-03 1944-08-15 Rossi Irving Continuous casting of metals
US3022540A (en) * 1953-10-06 1962-02-27 Continental Can Co Dipping apparatus for fabricating flexible containers
US3183292A (en) * 1962-05-25 1965-05-11 Dvoracek Frank Plastic molding apparatus and method
US3414471A (en) * 1964-03-26 1968-12-03 Henry Boucher Fils & Cie Pulp molding apparatus
US3379804A (en) * 1964-06-10 1968-04-23 Konink Sphinx Ceramique V H Pe Method of the production of a body from a slip in a porous mold
US3380509A (en) * 1964-08-17 1968-04-30 Suedwestfalen Ag Stahlwerke Method of pressure treatment of metallic melts, especially steel melts
US3439734A (en) * 1965-12-06 1969-04-22 Foseco Trading Ag Apparatus for forming hot top liners

Also Published As

Publication number Publication date
GB1212566A (en) 1970-11-18
NO120851B (en) 1970-12-14

Similar Documents

Publication Publication Date Title
US4982777A (en) Countergravity casting method and apparatus
US5657812A (en) Metal-casting apparatus and method
US2195960A (en) Apparatus for casting metal
US2448903A (en) Displacement type casting apparatus
US5611980A (en) Apparatus and method for slip casting
US4571270A (en) Process and autoclave for dewaxing mold for lost wax casting
US3568755A (en) Machine for the manufacture of articles of a slurry of solid matter in a liquid
US3200451A (en) Ingot casting machines
US2798266A (en) Core and mold blowing method and apparatus
EP1428599A1 (en) Method, apparatus and system for casting metal melt and other fluid materials
US3653426A (en) Furnace pouring and casting system
US3446266A (en) Investment casting apparatus
CN209393948U (en) A kind of full-automatic plus shot device for shell moulded casting
US2779071A (en) Control system for sand blowing apparatus
US3231946A (en) Apparatus for forming ceramic shell molds
US2116630A (en) Method of casting tubular members
US2997757A (en) Foundry mold
SU482243A1 (en) Installation for pouring melts under low pressure, predominantly with backpressure
US2471049A (en) Apparatus for coating ingot molds
US3645320A (en) Apparatus for vacuum forming hot top bottom rings
JP2845390B2 (en) Compressed air supply method in mold making apparatus
JP3097975B2 (en) Gate cleaning device
PL169294B1 (en) Apparatus for orderly placing and closing the casting moulds
GB1473462A (en) Sand blowing head
US2646607A (en) Means for preventing collapse of molded concrete products when core is withdrawn