Hydrocyclone Installation

Hydrocyclones should be located so that underflow can be moved away
with a minimum of trouble and washdown water and so that they are
accessible for maintenance and evaluation.

Discharge overflow should return to the circulating system into
a compartment immediately downstream of the suction compartment;
however, the discharge overflow compartment must be bottom equalized
with the suction compartment, and drilling fluid should backflow from
the discharge tank into the suction tank at all times. The hydrocyclones
should process all of the drilling fluid entering the suction compartment.
Ensure that all drilling fluid entering the discharge compartment has
been processed by the hydrocyclones.

Centrifugal feed pumps should be located so that they have flooded
suction and minimum suction line length with few elbows and turns,
to keep friction losses at a minimum.

A centrifugal pump may stir its suction compartment with mud guns.
Mud jet mixers should not be supplied with fluid from other parts of
the drilling-fluid system. Preferably, mechanical agitators will be used
in the removal section.

Keep the end of the discharge line above the surface of the mud in
the receiving tank, to avoid creating a vacuum. Overflow should be
introduced into the next compartment downstream at approximately a
45 angle so that lines will be kept full and a siphoning vacuum (which
would pull more solids into the overflow discharge) avoided. When
hydrocyclones are mounted more than 5 feet above the liquid level of the
mud tanks, a siphon breaker should be installed in the overflow manifold
from the cones.

For a hydrocyclone troubleshooting guide, see Table 1.

Table 1.
Hydrocyclone Troubleshooting Guide

Symptom Probable Cause(s) and Action
Cones continually plug at apex,

some cones OK

Partially plugged feed inlet or outlet.

Apex(es) too small. Remove cone,

clean out lines. Check shaker for

torn screens or bypassing.

Some cones losing whole mud in a stream Plugged cone feed inlet allows backflow

from overflow manifold

Low feed head Check centrifugal pump operation:

rpm voltage, etc. Check shaker for

torn screens or bypassing. Check

for obstructions in line, solids

settling, partially closed valve.

Cones discharge dry solids Apex too small. Need more cones?
Vacuum in manifold discharge

(long drop into pits?)

Install siphon breaker
Heavy discharge stream Overloaded cones. Increase apex size

and/or install more cones

Mud % solids increasing Insufficient cone capacity, install

more cones. Solids may be too

small, finer shaker screens?

High mud losses Cone apex too large, reduce.
Centrifuge cyclone discharge? Reduce cone sizes.
Unsteady cone discharge, varying feed head Air or gas in feed
Aerated mud downstream of hydrocyclone Route overflow into trough to allow

air breakout

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