| 摘要 |
A process for producing hollow items, for instance foundry cores by reacting a catalyst gas with binder coated on mineral granular material includes providing a core box having a pattern formed of microporous material and investing binder-coated granular material into a volume defined by the pattern. The core box is then sealed so that the volume encloses a gas, for instance air at atmospheric pressure, within the granular material. A catalyst gas is applied at a predetermined pressure through the pattern so that the catalyst gas exerts a uniform pressure from the interior surface of the pattern against the enclosed air volume. The catalyst gas will penetrate a distance through the granular material for curing same determined by an equilibrium condition being reached between the applied catalyst gas pressure and air pressure which results from contraction of the volume.
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