GB1562725A - Preparing foundry forms - Google Patents
Preparing foundry forms Download PDFInfo
- Publication number
- GB1562725A GB1562725A GB4546976A GB4546976A GB1562725A GB 1562725 A GB1562725 A GB 1562725A GB 4546976 A GB4546976 A GB 4546976A GB 4546976 A GB4546976 A GB 4546976A GB 1562725 A GB1562725 A GB 1562725A
- Authority
- GB
- United Kingdom
- Prior art keywords
- form box
- sealing means
- diaphragm
- mixture
- box
- 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
Links
- 238000007789 sealing Methods 0.000 claims description 64
- 239000000203 mixture Substances 0.000 claims description 38
- 238000000034 method Methods 0.000 claims description 32
- 239000011230 binding agent Substances 0.000 claims description 13
- 239000012530 fluid Substances 0.000 claims description 11
- 239000004576 sand Substances 0.000 claims description 6
- 239000013536 elastomeric material Substances 0.000 claims description 5
- 239000012466 permeate Substances 0.000 claims description 3
- 230000000717 retained effect Effects 0.000 claims description 2
- 239000007789 gas Substances 0.000 description 19
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000005266 casting Methods 0.000 description 3
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- RRLHMJHRFMHVNM-BQVXCWBNSA-N [(2s,3r,6r)-6-[5-[5-hydroxy-3-(4-hydroxyphenyl)-4-oxochromen-7-yl]oxypentoxy]-2-methyl-3,6-dihydro-2h-pyran-3-yl] acetate Chemical compound C1=C[C@@H](OC(C)=O)[C@H](C)O[C@H]1OCCCCCOC1=CC(O)=C2C(=O)C(C=3C=CC(O)=CC=3)=COC2=C1 RRLHMJHRFMHVNM-BQVXCWBNSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- BICAGYDGRXJYGD-UHFFFAOYSA-N hydrobromide;hydrochloride Chemical compound Cl.Br BICAGYDGRXJYGD-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 235000010269 sulphur dioxide Nutrition 0.000 description 1
- 239000004291 sulphur dioxide Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
- B22C15/23—Compacting by gas pressure or vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/03—Sand moulds or like moulds for shaped castings formed by vacuum-sealed moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/12—Treating moulds or cores, e.g. drying, hardening
- B22C9/123—Gas-hardening
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Devices For Molds (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Mold Materials And Core Materials (AREA)
Description
(54) PREPARING FOUNDRY FORMS
(71) We, BAKER PERKINS HOLD
INGS LIMITED, of Westfield Road,
Peterborough, PE3 6TA, a British
Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- BACKGROUND OF THE INVENTION
The present invention relates to a method of preparing a foundry form by a cold set process, comprising introducing a mixture of foundry sand and a binder into a form box, covering an open end of the form box with a sealing head comprising a flexible diaphragm, and applying suction to the form box to draw the diaphragm against a surface of the mixture to compact the mixture in the form box. The invention also relates to apparatus for carrying out the method.
The invention is primarily applicable to foundry moulds, i.e. to the forms for shaping the outside of the castings. However, the invention can also be applied to the mould cores, i.e. the forms for shaping the interior of the castings, if the cores are of such a shape that the diaphragm arrangement can be used. For this reason, the unusual terms "foundry form" and "form box" are used herein to comprise both the foundry mould and mould box, and the mould core and
core box. The mould box itself can contain a pattern or can have a plain bottom, e.g.
contain a plain platen, to form a flat side on the casting.
The method and apparatus referred to above are described in British Patent
Specification No. 1 470 672. However, it has been found that the method and apparatus can be improved for use when applying a fluid hardening medium to harden the mixture in the form box. The fluid hardening medium is usually a gas, and can act either as a catalyst or a hardening agent.
The most common such process is the
CO2 process in which gaseous CO2 is
introduced to the form box as a hardening
agent to react with a sodium silicate mixture
binder. However, other processes can be
used, and the invention can be applied to
any chemical binder system which utilizes a
fluid hardening agent. For example, with
certain types of resins, a catalytic hardening
agent may be in the form of an acidic gas;
the acid components of the gas may be normally gases or may be normally liquid and in the form of vapours, such
components including sulphur dioxide, chlorine, aluminium chloride, hydrogen chloride and hydrogen bromide.
THE INVENTION
The present invention provides a method of preparing a foundry form as set forth in
Claim 1, and apparatus for preparing a foundry form as set forth in Claim 4.
Using the invention, the initial vacuum applied to the mixture in the form box evacuates much of the air and gives the incoming hardening fluid a clear volume in which to "wash" the particles of the mixture without itself having to push out the air, and if desired, there can be a further application of vacuum to improve the penetration of the fluid hardening medium. Compared to prior art processes in which the gas was merely applied to the top of the open form box, gas usage can be reduced by 1/3, and the speed with which the gas is applied can be considerably accelerated, leading also to shorter hardening periods due to better gas/particle contact.
BRIEF DESCRIPTION OF THE DRAW
INGS
The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of apparatus in accordance with the invention, showing parts in vertical section;
Figure 2 is a vertical section of part of the
apparatus of Figure 1; and
Figure 3 is a vertical section of part of the
apparatus of Figure 1, showing a minor
modification, and showing the form box when pressure has been applied to the mixture therein.
DETAILED DESCRIPTION OF THE
DRAWINGS
The general arrangement shown in Figure 1 is very similar to that disclosed in British
Patent Specification No. 1 470 672, and will only be described very briefly.
Figure 1 shows an in-line foundry plant wherein mould or core boxes 1 abut each other, and are moved upright in the direction of the arrow 2 along an upper conveyor run by means of a ram 3, and are moved inverted in the direction of the arrow 4 along a lower conveyor run by means of a ram 5. The path comprises a roll-over station A, a filling station B, a compacting and gassing station C, a curing station D, a roll-over station E, a discharge station F and a return line G.
At the filling station B, each successive form box 1 is filled as described in British
Patent Specifications No. 1 418491 and No.
1 470672, a fixed upset frame being used both for filling and strickling as the form box 1 moves on.
At the compacting station C, there are upper and lower sealing means in the form of sealing heads 7 and 8, the top sealing head 7 being fixed in position slightly above the path of the form boxes 1 but the bottom sealing head 8 being vertically movable by any suitable means, for instance two small rams 9. The operation at the compacting station C is described in more detail below with reference to Figures 2 and 3. After compacting, curing and inversion, the completed form is discharged by compressed air applied by means of a sealing head 10 and is discharged onto a conveyor 11.
As shown in Figures 2 and 3, the form box 1 has an open top and bottom and its side walls have pattern plate retaining means in the form of spaced supports or lugs 12 for retaining a pattern plate 13 adjacent the bottom of the form box 1. The pattern plate 13 in the embodiment illustrated in Figures 2 and 3 carries a pattern 14, and the pattern plate 13 and pattern 14 may be perforated in any suitable manner, as is illustrated in
Figure 3 but not in Figure 2. The pattern plate 13 terminates a small distance, say 1.5 mm, short of the side walls of the form box 1 so that even in Figure 2, air can be drawn out into the bottom of the form box 1, passing around the outside of the pattern plate 13 between the lugs 12. As an alternative which is not illustrated, the perforated pattern plate 13 of Figure 3 could be permanently fixed within the form box 1 and sealed to the side walls thereof.
The top sealing head 7 carries a soft frame-shaped seal 15 for sealing against the top of the form box 1 and first and second securing frames 16, 17. By means of respective fixing frames 18, 19 first and second diaphragms 20, 21 are secured to the top sealing head 7. The first diaphragm 20 is made of a thin, perforated elastomeric material such as rubber or synthetic rubber and the second diaphragm 21 is made of an -imperforate but like material. There is a duct 22 leading to the space between the frames 16, 17 and thus to the space between the diaphragms 20, 21.
The lower sealing head 8 has a seal 23 for engaging the bottom of the form box 1 and sealing against either the main aperture formed by the bottom of the form box 1 or (in another alternative not illustrated) smaller apertures in the pattern plate 12.
There is a suction duct 24. It will be noted that an identical head 8 can be mounted below the filling station B, for use in filling the form box 1.
As shown in Figure 1, in the compacting station the rams 9 lift the bottom sealing head 8 against the bottom of the form box 1 and thus lift the form box 1 up against the top sealing head 7, sealing the form box 1 securely between the two heads 7, 8. Using a programmed valve box (not shown) suction of the order of 20 to 26 inches Hg (about 0.7 to 0.9 Kg/cm2) is applied to the duct 24.
This withdraws air from the sand/binder mixture 25 in the form box 1 and draws the second diaphragm 21 against the first diaphragm 20 and thus the first diaphragm 20 against the top surface of the mixture 25 to compact the mixture around the pattern
14. If desired, the vacuum can be continued, but preferably hardening gas is supplied to the duct 22 at the same time as the vacuum is cut off from the duct 24; subsequently the vacuum is re-applied to the duct 24 whilst hardening gas continues to be supplied through the duct 22, and then the vacuum and gas are cut off simultaneously.
However, parameters such as the length of time of application of the vacuum and gas and the overlap can be varied as desired to achieve proper contact of the mixture 25 with the gas and avoiding gas wastage, the parameters depending on factors such as the size of the mould, the amount of gas dispersion required and the shape of the pattern, the vacuum itself only being a partial vacuum. A suitable pressure for the gas is about 1 Kg/cm2, and it will be seen that when the gas is applied, the gas separates the diaphragms 20, 21 and retains the first diaphragm 20 in pressure contact with the mixture 25, thereby preventing any disturbance of the compacted mixture whilst the gas passes through the diaphragm 20 and permeates the mixture 25 and reacts with the binder to initiate setting or hardening of the mixture 25.
After sufficient gassing, the rams 9 are retracted to lower the bottom sealing head 8 and thus the form box 1, and if desired, heated air may be blown on the setting mixture to accelerate the setting time (in spite of this, the process is still called a "cold set" process).
It will be understood that the in-line plant shown in Figure 1 could be replaced by any suitable alternative plant, such as a conventional rotary table plant.
WHAT WE CLAIM IS:
1. A method of preparing a foundry form by a cold-set process, comprising: introducing a mixture of foundry sand and a binder into a form box; covering an open end of the form box with sealing means comprising a first, fluidpervious, flexible diaphragm backed by a second, impervious, flexible diaphragm; applying suction to the form box to draw the second diaphragm against the first diaphragm and the first diaphragm against the surface of the mixture in the form box to compact the mixture; and subsequently introducing a fluid hardening medium between the first and second diaphragms so that is passes through the first diaphragm, permeates the mixture within the iormox, and causes the binder to harden the mixture.
2. The method of Claim 1, wherein the suction is applied to the form box by engaging second sealing means with the opposite end of the form box and applying suction to the second sealing means.
3. The method of Claim 2, wherein successive form boxes are delivered horizontally between the first and second sealing means, the first and second sealing means being respectively above and the below the form box, the second sealing means is lifted against the bottom of the form box and lifts the form box up against the first sealing means, suction is applied to the second sealing means, the fluid hardening medium is introduced between the first and second diaphragms, and the second sealing means is lowered to lower the form box away from the first sealing means.
4. Apparatus for preparing a foundry
form by a cold-set process using a mixture
of foundry sand and a binder, comprising: a pair of opposed sealing means for sealing
against opposite ends of a form box, the first
sealing means being for covering an oen end of the form box and comprising a first,
fluid-pervious, flexible diaphragm backed
by a second, impervious, flexible
diaphragm, and the second sealing means
being for sealing against at least one
aperture in the opposite end of the form
box; means for retaining the first and second sealing means against the respective ends of the form box; means for applying suction to the second sealing means to draw the second diaphragm against the first diaphragm and the first diaphragm against the surface of the mixture in the form box to compact the mixture; and
means for subsequently introducing a fluid
hardening medium between the first and
second diaphragms so that is passes through the first diaphragm, penetrates the mixture within the form box, and causes the binder to harden the mixture.
5. The apparatus of Claim 4, and including a form box, the form box having an open top and an open bottom and means for retaining a pattern plate adjacent the bottom of the form box, the second sealing means being for sealing against the open bottom of the form box.
6. The apparatus according to Claim 5, wherein the pattern plate is retained on spaced supports projecting from the form box walls.
7. The apparatus of any one of Claims 4 to 6, wherein the pattern plate is perforated.
8. The apparatus of Claim 7, wherein the bottom of the form box is closed by the pattern plate, which is fixed within the form box.
9. The apparatus of any one of Claims 4 to 8, and including horizontal conveying means for successive form boxes, and the first and second sealing means are respectively above and below the conveying means.
10. The apparatus of Claim 9, wherein the first sealing means is stationary whilst the sealing means retaining means comprises means for lifting the second sealing means against the bottom of the form box and thus lifting the form box up against the first sealing means.
11. The apparatus of any one of Claims 4 to 10, wherein the first diaphragm is a thin, perforated sheet of elastomeric material and the second diaphragm is a thin, imperforate sheet of elastomeric material.
12. The apparatus of any one of Claims 4 to 11, wherein the first diaphragm is secured to a first closed frame and the second diaphragm is secured to a second closed frame spaced within the first closed frame, said introducing means comprising a duct leading to the frame-shaped gap between the first and second frames.
13. The method of Claim 1 and performed using the apparatus of any one of Claims 4 to 12.
14. A method of preparing a foundry form by a cold set process, substantially as herein described with reference to, and as shown in, the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (15)
1. A method of preparing a foundry form by a cold-set process, comprising: introducing a mixture of foundry sand and a binder into a form box; covering an open end of the form box with sealing means comprising a first, fluidpervious, flexible diaphragm backed by a second, impervious, flexible diaphragm; applying suction to the form box to draw the second diaphragm against the first diaphragm and the first diaphragm against the surface of the mixture in the form box to compact the mixture; and subsequently introducing a fluid hardening medium between the first and second diaphragms so that is passes through the first diaphragm, permeates the mixture within the iormox, and causes the binder to harden the mixture.
2. The method of Claim 1, wherein the suction is applied to the form box by engaging second sealing means with the opposite end of the form box and applying suction to the second sealing means.
3. The method of Claim 2, wherein successive form boxes are delivered horizontally between the first and second sealing means, the first and second sealing means being respectively above and the below the form box, the second sealing means is lifted against the bottom of the form box and lifts the form box up against the first sealing means, suction is applied to the second sealing means, the fluid hardening medium is introduced between the first and second diaphragms, and the second sealing means is lowered to lower the form box away from the first sealing means.
4. Apparatus for preparing a foundry
form by a cold-set process using a mixture
of foundry sand and a binder, comprising: a pair of opposed sealing means for sealing
against opposite ends of a form box, the first
sealing means being for covering an oen end of the form box and comprising a first,
fluid-pervious, flexible diaphragm backed
by a second, impervious, flexible
diaphragm, and the second sealing means
being for sealing against at least one
aperture in the opposite end of the form
box; means for retaining the first and second sealing means against the respective ends of the form box; means for applying suction to the second sealing means to draw the second diaphragm against the first diaphragm and the first diaphragm against the surface of the mixture in the form box to compact the mixture; and
means for subsequently introducing a fluid
hardening medium between the first and
second diaphragms so that is passes through the first diaphragm, penetrates the mixture within the form box, and causes the binder to harden the mixture.
5. The apparatus of Claim 4, and including a form box, the form box having an open top and an open bottom and means for retaining a pattern plate adjacent the bottom of the form box, the second sealing means being for sealing against the open bottom of the form box.
6. The apparatus according to Claim 5, wherein the pattern plate is retained on spaced supports projecting from the form box walls.
7. The apparatus of any one of Claims 4 to 6, wherein the pattern plate is perforated.
8. The apparatus of Claim 7, wherein the bottom of the form box is closed by the pattern plate, which is fixed within the form box.
9. The apparatus of any one of Claims 4 to 8, and including horizontal conveying means for successive form boxes, and the first and second sealing means are respectively above and below the conveying means.
10. The apparatus of Claim 9, wherein the first sealing means is stationary whilst the sealing means retaining means comprises means for lifting the second sealing means against the bottom of the form box and thus lifting the form box up against the first sealing means.
11. The apparatus of any one of Claims 4 to 10, wherein the first diaphragm is a thin, perforated sheet of elastomeric material and the second diaphragm is a thin, imperforate sheet of elastomeric material.
12. The apparatus of any one of Claims 4 to 11, wherein the first diaphragm is secured to a first closed frame and the second diaphragm is secured to a second closed frame spaced within the first closed frame, said introducing means comprising a duct leading to the frame-shaped gap between the first and second frames.
13. The method of Claim 1 and performed using the apparatus of any one of Claims 4 to 12.
14. A method of preparing a foundry form by a cold set process, substantially as herein described with reference to, and as shown in, the accompanying drawings.
15. Apparatus for preparing a foundry form
by a cold-set process, substantially as herein described with reference to, and as shown in, the accompanying drawings.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4546976A GB1562725A (en) | 1974-07-15 | 1976-11-02 | Preparing foundry forms |
| FR7732773A FR2369036A2 (en) | 1974-07-15 | 1977-10-28 | IMPROVEMENTS IN THE MANUFACTURING PROCESSES OF MOLDS AND FOUNDRY CORES |
| US05/847,931 US4129165A (en) | 1976-11-02 | 1977-11-02 | Preparation of foundry moulds and cores |
| DE19772749527 DE2749527A1 (en) | 1974-07-15 | 1977-11-02 | METHOD AND DEVICE FOR THE MANUFACTURING OF FOUNDRY SHAPES BY COLD CURING OR SETTING |
| IT29268/77A IT1114445B (en) | 1976-11-02 | 1977-11-02 | METHOD AND APPARATUS FOR THE PRODUCTION OF FOUNDRY SHAPES AND SOULS |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3132574A GB1470672A (en) | 1974-07-15 | 1974-07-15 | Manufacture of foundry moulds and cores |
| GB4546976A GB1562725A (en) | 1974-07-15 | 1976-11-02 | Preparing foundry forms |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1562725A true GB1562725A (en) | 1980-03-12 |
Family
ID=26260848
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4546976A Expired GB1562725A (en) | 1974-07-15 | 1976-11-02 | Preparing foundry forms |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE2749527A1 (en) |
| FR (1) | FR2369036A2 (en) |
| GB (1) | GB1562725A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5855149A (en) * | 1981-09-28 | 1983-04-01 | Sintokogio Ltd | Gas hardening type molding device for master mold |
| DE3145623C2 (en) * | 1981-11-17 | 1984-12-06 | Sintokogio, Ltd., Nagoya, Aichi | Method of making a casting mold |
| FR2516819A1 (en) * | 1981-11-26 | 1983-05-27 | Sintokogio Ltd | Sand mould prepn. - by applying a vacuum for sand compression and penetration by hardening gas |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3156958A (en) * | 1964-11-17 | Foundry molding machine | ||
| FR1224772A (en) * | 1958-05-19 | 1960-06-27 | Double membrane machine for sand mold making | |
| FI46335C (en) * | 1971-02-11 | 1973-03-12 | Ahlstroem Oy | Process for curing molds or cores by means of combustion gases. |
| GB1470672A (en) * | 1974-07-15 | 1977-04-21 | Baker Perkins Holdings Ltd | Manufacture of foundry moulds and cores |
-
1976
- 1976-11-02 GB GB4546976A patent/GB1562725A/en not_active Expired
-
1977
- 1977-10-28 FR FR7732773A patent/FR2369036A2/en active Pending
- 1977-11-02 DE DE19772749527 patent/DE2749527A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| FR2369036A2 (en) | 1978-05-26 |
| DE2749527A1 (en) | 1978-05-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |