sand is disposed of in the same manner as outlined in the foregoing description.

In one large foundry in which there are two screening and treating plants, the equipment is provided with four knockout positions. The molds are brought to the knockout positions after pouring, by traveling cranes. The sand is jarred

out of the flask by means of heavy jarring machines, which are essentially similar to the jarring machines used for molding operations. The sand then falls onto the pan conveyor and is carried through the same process of treatment and screening as described above.

In the handling of molding sand, a few important general principles should be kept in mind. It is never desirable to handle tempered sand in a bucket elevator if other means can be used. The reason for keeping away from the bucket elevator for this service is that the tempered sand has a tendency to fill up the buckets and requires frequent cleaning in order to maintain the operating capacity. If the sand is handled

FIG. 7-INDIVIDUAL OVERHEAD SAND HOPPERS

as it comes from the molds it is generally dry enough so as not to involve this difficulty.

Advantages of Flat Belt Conveyor

For the distribution of the tempered sand, in my judgment, there is nothing so satisfactory as the flat rubber conveyor belt, even though reciprocating flight conveyors have been used with more or less success. One of the main objections to the reciprocating conveyor is the amount of power required to operate it as compared with the belt conveyor. A further objection is that there is a marked tendency to produce small balls of sand about the size of peas or beans which are detrimental to the obtaining of smooth castings.

The use of the rubber conveyor belt is strongly recommended because of the fact that it possesses a smooth operating surface which cannot become impregnated with the sand and which resists wear for a long period. The writer recently viewed a belt of this character. which had operated through the equivalent of 9 years continuous daily service. The belt is

240 feet, center to center, and handles approximately 250 tons of sand daily. It has been operating for 7 years but during the years 1917 and 1918 worked double shift. At the time it was viewed by the writer it was still in good working condition.

The device for removing the tempered sand from the belt conveyors is extremely simple and consists of nothing more

than a curved plate placed so as to act like a plow and turn the sand over at the desired point. These plow plates are hinged at one end so that they may be lifted out of the way, allowing the sand to pass to any other desired point.

Removing Sand from Storage Bins

One of the principal difficulties which has been met in foundry sand handling has been the problem of properly with

drawing the tempered sand from the storage bin after it has been placed there. Many expedients have been used but it is the writer's opinion that the type of feeder shown in Fig. 8 meets the condition more satisfactorily than any other with which he is familiar. It is easily adjusted and seems to have