Page 24 - Pipeline Rules of Thumb Handbook

General Information 11

Wire-Rope Trouble Cause Wire-Rope Trouble Cause

high speed, rope slipping, t. Excessive flattening or Heavy overload, loose winding
concentration of vibration at crushing. on drum, or cross winding. Too
dead sheave or dead-end infrequent cut-offs on working
anchor, undersized grooves end of cable-tool lines.
and sheaves, and improper Improper cutoff and moving
selection of rope program for cable-tool lines.
construction. Prolonged
u. Bird-caging or Sudden unloading of line such
bending action over spudder
core-popping. as hitting fluid with
sheaves, such as that due to
excessive speed. Improper
hard drilling.
drilling motion or jar action.
Use of sheaves of too small
s. Spiraling or curling. Allowing rope to drag or rub diameter or passing line
over pipe, sill, or any object around sharp bend.
during installation or v. Whipping off of rope. Running too loose.
operation. It is recommended
that a block with sheave w. Cutting in on drum. Loose winding on drum.
diameter 16 times the nominal Improper cutoff and moving
wire-rope diameter, or larger, program for rotary drilling lines.
be used during installation of Improper or worn drum
the line. grooving or line turn-back plate.

Capacity of drums

The capacity of wire line drums may be figured from the where (see below) M = rope capacity of drum, in.
following formula: A = depth of flange, in.
B = diameter of drum, in.
C = width of the drum between flanges,
M = (A + B) ¥ A ¥ C ¥ K in.
K = constant depending on rope size
shown below
Rope Size K Rope Size K

3
/ 8 1.86 1 .262
7 1
/ 16 1.37 1 / 8 .207
1 1
/ 2 1.05 1 / 4 .167 Figure 1. Capacity of wire line
9 3
/ 16 .828 1 / 8 .138 drums.
5 1
/ 8 .672 1 / 2 .116
3 5
/ 4 .465 1 / 8 .099
7 3
/ 8 .342 1 / 4 .085
BELTS AND SHAFTS

Determine length of a V-belt

Rule: To find the nominal length of a V-belt, lay the belt on two circles, in inches. The belt size is then twice this figure,
a table, and place within it a pair of circular objects of the plus 5.14 times the diameter of the circles. This value, for any
same diameter (flanges, tin cans, or whatever may be at hand). standard belt, should be a whole number of inches, which is
Pull them apart until the belt is fully extended without the belt size.
stretching. Then measure the shortest distance between the V-belts are made in four standard sections, classified as A,