Core box with air vents integrated in pins

Abstract

The invention relates to sand casting and more specifically to sand casting of a heat exchanger element with pins and / or fins. The invention provides a core box for sand casting of workpieces comprising pins and / or fins. The core box molding surface comprises at least one air vent and pins and / or fins. The at least one air vent is integrated in at least one pin or fin.

Description

DESCRIPTION[0001]1. Technical Field[0002]The present invention relates to sand casting and all casting processes where sand core are used, and more in particular to a sand casting for production of pin finned workpieces.[0003]The invention further relates to such workpieces, e.g. heat exchanger elements provided with a dense array of pinned fins.[0004]2. Background Art[0005]Heat exchanging surfaces are commonly provided with pin fins. These pin fins provide an enlargement of the heat exchanging surface, as more surface of the heat exchanger is in contact with the cooling or heating fluid.[0006]A further enlargement of the heat exchanging surface can be obtained by using thinner and thus also shorter pins which also allows more pins on the same surface area, thereby obtaining a greater surface content, as described in EP1722172. Still more enlargement of the heat exchanging surface is however limited by the inter pin or fin spacing, reduction below which it is impossible or impractic...

AI Technical Summary

Benefits of technology

[0007]It is an object of the present invention to escape the limitations of the sand casting process for further enlargement of the heat exchanging surface. More precisely, the object of the present invention is to provide an improved sand casting method enabling the enlargement of the heat exchanging surface.

[0009]The present invention mitigates this restriction by providing air vents in or integrated in the pins and / or fins. An aspect of the present invention provides a core box for sand casting of workpieces comprising pins and / or fins. The core box molding surface comprises at least one air vent and pins and / or fins. The at least one air vent is integrated in at least one pin or fin. The integration of the air vents in the pins and / or fins allows a densification of the pin and / or fin array, which thereby enlarges the heat exchanging surface. This is especially useful when relatively big air vents are needed for sufficient venting in the core box, but a large heat exchanging surface of the cast heat exchanger is desired.

[0011]Coming back to the present invention, the pins used here can have any appropriate diameter. Preferably, the pins have a diameter of 3.0 mm or smaller. This enables a further enlargement of the heat exchanging surface of the heat exchanger element produced with the core box according to the present invention.

[0015]The integration of the air vents in the pins and / or fins makes it now possible to make more dense arrays of pins and / or fins. This more dense array of pins and / or fins in the core box for sand casting enables the enlargement of the heat exchanging surface of pin and / or fin containing heat exchanger elements produced by use of such core box.

[0017]Such heat exchangers have more heat exchanging surface, for a slightly increased heat exchanger weight, which allows an equal or even better thermal inertia of the system and also the reaction time stays the same or becomes even better.

Problems solved by technology

Still more enlargement of the heat exchanging surface is however limited by the inter pin or fin spacing, reduction below which it is impossible or impracticable to go with present manufacturing methods in an effort to increase surface area.

Images