Specifications

Document No. DER04098 OPERATING INSTRUCTIONS

Page 2 of 19 Effective Date 06 Jun 08

PURGE SYSTEM (HAZARDOUS ENVIRONMENT ONLY)

Only the centrifuge operating in a hazardous environment is equipped with the purge system.

During startup, the purge system drives out all gases from the cabinet interior and then maintains

positive pressure within the control cabinet to prevent potentially explosive gases from entering.

Operation of the purge system is initiated when sufficient air pressure is sensed inside the

cabinet. A 14-minute rapid purge cycle at 16 CFM then occurs, while the purge system prevents

power from being applied to the cabinet interior. At the end of the rapid purge cycle, the purge

system closes the main contactor that permits power to flow to the cabinet interior. A continuous 2

CFM purge then begins and continues both during and after centrifuge operation. It is preferable

to keep the cabinet pressurized. If at any time a loss of cabinet pressure is detected, the main

contactor will immediately open, disconnecting power. The 14-minute rapid purge is then repeated

before power is re-established.

CONTROL SCREENS

The screens that appear on the control panel provide the operator interface to the centrifuge for

operation of the control system for startup, monitoring, and shutdown. The paragraphs below

describe the functions of the principal screens used in centrifuge operation.

Home

Following the purge cycle, power is applied to the cabinet. The Home screen (Figure 4098-1) then

appears on the control panel, permitting selection of any of the following options:

Option Screen or Function Displayed

Operation - Operation screen (Figure 4098-2) used to start the centrifuge and monitor

performance.

Clean Out - Clean Out screen (Figure 4098-3) permits selection of automatic or manual

clean out cycles, which facilitate removal of excess solids that are impeding

conveyor rotation. If MANUAL is selected, the conveyor may be jogged between

forward and reverse to assist in clean out process. All clean out cycles are timed

to prevent damage to equipment.

Cent. Status - Status screen (Figure 4098-4) presents all current operational information such

as bearing temperatures, vibration switch condition, centrifuge operating hours,

and status of air conditioner.

Alarms - Alarms screen (Figure 4098-5) permits the operator to view current alarm

messages of bowl, conveyor, and pump variable frequency drives.

Brg Temps - Bearing temperature screen (Figure 4098-6) graphically displays liquid and solid

end bearing temperatures over the selected time period.

Setup - Setup screen (Figure 4098-7) allows the operator to set display panel

brightness, select temperature unit, and view feed pump characteristics.

screen used to limit operator access to Monitor Operation screen only.

Motor Torqs - Bowl and conveyor motor torque (Figure 4098-9) presented graphically over the

selected time period.