This is the simplest form of green sand molding, particularly suitable for solid patterns. The entire mold is made in foundry floor or in bed of sand above floor level for inconvenience in working and pouring. No molding box is necessary and the upper surface of the mold is open to air. The sand in the foundry floor is made loose and perfectly leveled to obtain uniform thickness of the casting. As there is no head of metal the sand may be rammed lightly, just hard enough to support the weight of metal only. After proper leveling, the pattern is pressed in the sand bed for making mold. The pouring basin is built up at one end of the mold, and the overflow channel is cut at the sides of the cavity at the exact height from the bottom face of the mold to give the desired thickness
CONSTRUCTION OF SIMPLE CARBURETOR : The main Components of Simple Carburetor are : Float Chamber, float, nozzle, venturi, throttle valve, inlet valve, and metering jet . In the float chamber, a constant level of petrol is maintained by the float and a needle valve. The float chamber is ventilated to atmosphere. This is used to maintain atmospheric pressure inside the chamber. The float which is normally a metallic hollow cylinder rises and closes the inlet valve as the fuel level in the float chamber increases to certain level. The mixing chamber contains venturi, nozzle and throttle valve. The venturi tube is fitted with the inlet manifold. This tube has a narrow opening called venturi. A nozzle is provided just below the centre of this venturi. The nozzle keeps the same level of petrol as that of the level in the float chamber. The mixing chamber has two butterfly valves. One is to allow air into the mixing chamber known as choke valve. The other is to al...
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