Hoisting drum ( drilling rig ) – Readyzone

draw - works

Fig. 1 – The Draw Works

Hoisting drum

The drilling line is spooled on the hoisting drum and its vertical movement ( i.e. up and down ) is derived from the rotation of the hoisting drum. The length of line spooled depends on the number of sheaves used in the travelling block and derrick height. The drum is powered from the main drive shaft through a jack shaft assembly using roller chains and sprockets.

The input power is used to rotate the drum during hoisting by engagement of high or low air clutches, causing the drilling line to spool onto the drum. For lowering, the drum is allowed to freewheel and the weight of the travelling block and other components will cause the drilling line to unreel.

A special design feature of the hoisting drum is a two-step Spirallel grooving, in which the drum grooves are parallel to the drum end flanges and kick over half a pitch in 450 every 1800 . This design means that the wraps of drilling line on the drum are mostly parallel and allow the line to spool correctly at high speed. Grooves also provide a much better support for the first layer of the drum than is possible with a smooth drum.

As a rule of thumb, the draw works should have 1 h.p. for each 10 ft to be drilled.

Related Links:-

*  Derrick              *  Drill collar             *  Kelly Drive

*  Drill pipe          *  Rotary table         *  Swivel

*  Tool joint          *  Draw works

Drum shaft group                             * Auxiliary brake

Cat shaft and coring reel group   

*  Brakes

Reference : H. Rabia, Oil Well Drilling engineering-Principles and Practice

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