 Hello friends, myself Dr. Narendra Kartikar, Assistant Professor, Department of Mechanical Engineering, Valachandra Institute of Technology, Solapur. Now we are going to discuss about the study of furnaces part 1. At the end of this session, students will be able to understand the construction and working of crucible furnace. The content for this discussion, introduction, what is furnace? Furnaces for casting processes, melting furnaces, selection of melting furnaces, crucible furnace in detail. Now initially, let us have a look what exactly the furnace means. On the image, you can see one of the type of furnace. The prime importance function of the furnace is to convert the solid metal into the liquid metal itself. Burning media or device is nothing but a furnace used for heating and melting, for providing heat to chemical reaction for processes like cracking. The furnace may be heated by fuel as in many furnaces, coke is used as a fuel. Some are operated by electrical energy, for example, electric arc furnace. Furnaces for casting processes, furnaces most commonly used in foundries are cupolas, direct fuel fired furnace, crucible furnace, electric arc furnace and induction furnace. Melting furnaces basically classified accordance with the which metal is going to be melt into the same. For gray cast iron, cupola, air furnace, rotary furnace, electric arc furnace, whereas steel, open earth furnace, electric arc furnace and so on. For nonferrous metals, normally the crucible furnaces which more specifically used for aluminum and copper, which further classified pit type, tilting type and which pit type, tilting type all these types we are going to see in a later stage. The pot furnaces, reverberatory furnaces, rotary furnaces, induction furnaces and so on. Let us have a look for selection of melting furnaces. The selection of foundry furnaces depend upon the various factors like initial cost of furnace, fuel cost, kind of metal are allowed to be melted, melting and pouring temperature of the metal to be cast, quantity of metal to be melted, cost of furnace repair and maintenance, cost of melting per unit weight of the metal, chances of metal to absorb impurities during melting, quantity of finished product desired, crucible furnace. Metal is melted without direct contact with burning fuel mixture, sometimes called as indirect fuel fired furnace. Container that is nothing but crucible is made up of refractory material or high temperature steel alloy. Crucible which is a refractory vessel made up of silicon carbide, graphite or some other refractory material. Used for specifically nonferrous metals such as bronze, brass, alloy of zinc and aluminum. There are three types of crucible furnace in foundry, lift out type, stationary type and tilting type. Let us have a look initially how the crucible furnace works. You can see over there that in a heavy brick wall structure crucible is present over there. Surrounding area rather the gap between crucible and heavy walled structure the gas plus air mixture is provided over there where actually the burning took place. As well as whatever the fumes are there those are escape out from the top side. Crucible furnace having refractory lining is shown in the particular image. Refractory walls of furnace interior with the burner blocks are also shown over here. At this stage of this session are you able to recall or share some of the casting parts with different ferrous and nonferrous metals which you had seen earlier anywhere in real time. Just enlist now let us move further for crucible furnace. The following figures shows the three different type of crucible furnace as mentioned lift out crucible stationary part from which the molten metal must be ladle and third one is a tilting part furnace. Let us have a look on sub figure A where the particular crucible furnace is supported with a support block and it can be taken out from the particular heavy walled structure directly lifting out that crucible and taking to the nearby pouring station is possible that is why called as the lift out crucible. Second one is further more heavy or strong structure with a more capacity the sub type present that is a stationary part in which the molten metal is present cannot be lift out directly but it can be taken out through the means of ladles whereas for the simplicity for the function of pouring purpose the tilting part furnace is developed. The sub figure C is more self explanatory that how tilting mechanism can be worked with a tilting handle operation likewise the ladles can be filled by tilting the crucible furnace itself and it can be taken over to the pouring station itself crucible furnace for melting of nonferrous metals its capacity may range from 30 to 150 kilograms type of crucible furnaces in further more classification pit furnace oil fire tilting furnace coke fired stationary furnace and pot furnace pit furnace the crucible is placed in a pit below the floor level it is fired with a coke the charge to be melted is placed in the coke is packed around the crucible natural draft is provided by a tall chimney many crucibles can be placed in a single pit after the metal is melted the covers are removed the crucible are lift out with the help of tongs and taken to pouring place this furnace is used for melting nonferrous metals whatever we had discussed can be compared and referred with this particular diagram you can see below the ground particular setup of crucible furnace is present let us have a more loop and try to recall whatever we had discussed going to the next type oil fired tilting furnace this furnace is used for melting nonferrous metals in small quantity and is fired by oil this furnace is mounted on two pedestal above the floor level for pouring the molten furnace is rotated by the geared hand wheel oil and air are admitted with the pressure through a nozzle the crucible is placed in the heating chamber and he is heated by the flame the furnace can be stopped whenever needed and temperature can be controlled easily they give lesser pollution whatever we had just discussed can be compared with this self-explanatory diagram you can see over here that oil is used as a fuel for heating purpose as well as the term in the title that is tilting can be referred over here with the help of the same it is easy to take out the molten metal from the furnace coke fire stationary furnace this furnace is used for melting nonferrous metal in small quantity this is placed above the floor level the crucible is placed in the heating chamber the heating chamber is lined with the refractory coke is used as a fuel and force draft is used a blower is used for supply of air to just visualize this particular coke fire stationary furnace this diagram will be helpful you can see over here the coke is used as a fuel over here the coke fire stationary furnace diagram is further more self-explanatory one pot furnace it is used for melting nonferrous metal like aluminium tin lead and magnesium it is made up of cast iron or steel and it is fired with a gasoline oil or coke molten metal is taken out from pot furnace by using ladles normal a capacity of 500 kg it is looking like like this the further more pot furnace diagram is self-explanatory with a labeling of all the parts the references for this particular discussion introduction to basic manufacturing processes and workshop technology by Rajendra Singh a textbook of workshop technology manufacturing processes by Khurmi Gupta and so on thank you