This document provides a procedure for cleaning a coolant purification centrifuge system. Key steps include: shutting off power and isolating coolant flow, opening the centrifuge housing and securing the cover, removing and disposing of the contaminated basket liner, replacing the cleaned liner, and restoring coolant flow and power to return the centrifuge to operation. Regular cleaning is important to maintain peak efficiency and minimize contamination in recycled coolant.

1. For change control: Reviewers: Approved by: For info:
Paul F. Geer James Scofield, Jr.
Sean Peterson
Richard Huston
James Scofield, Jr.
Sean Peterson
Richard Huston
Gene Martin
Cynthia Houston
Author: Paul F. Geer
Pages Incl. cover : 10
© LOGOS 2008. All rights reserved.
Reproduction in whole or in part is prohibited without the prior written consent of LOGOS.
Doc. ID / Version: XXXXXX / A
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DOC. TYPE: Standard Operating Procedure
Program:
Miscellaneous
Project:
Equipment Maintenance
Coolant Centrifuges: Cleaning Procedure
DOCUMENT CHANGE & HISTORY RECORD
Name
Last
Update
Status Version Comment
Paul F. Geer 8-Jul-08 Draft A Initial release.
Applicable Documents
Ref. Title Doc. Id
[1.1]
[1.2]
Tooling Required
Description 12NC
1 CROWBAR N / A
1 ALLEN WRENCH OR DRIVE RATCHET N / A
Digitally signed by Paul F. Geer
DN: cn=Paul F. Geer, o, ou,
email=pfgeer@sbcglobal.net,
c=US
Date: 2017.04.10 19:49:16 -04'00'

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TABLE OF CONTENTS
1 GENERAL ...........................................................................................................................3
1.1 PURPOSE.....................................................................................................................3
1.2 SCOPE .........................................................................................................................3
2 RESPONSIBILITIES............................................................................................................4
2.1 TECHNICIAN ................................................................................................................4
2.2 MANAGEMENT.............................................................................................................4
3 PROCESS DEFINITION ......................................................................................................5
3.1 OVERVIEW...................................................................................................................5
3.2 CENTRIFUGE SYSTEM COMPONENTS .....................................................................5
4 REQUIRED STEPS .............................................................................................................7
LIST OF FIGURES
Figure 3.1 View of Centrifugal Filtration System......................................................................................5
Figure 3.2 The Centrifuge Rotor ..............................................................................................................6
Figure 4.1 Control Panel: Location of Centrifuge-Off Button ...................................................................7
Figure 4.2 Isolating the Centrifuge from Coolant Flow.............................................................................7
Figure 4.3 Opening the Rotor Housing ....................................................................................................8
Figure 4.4 Cover Safety Hook..................................................................................................................8
Figure 4.5 Bolt Locations on the Rotor Cover..........................................................................................9
Figure 4.6 Removing the Rotor Cover from the Centrifuge Housing.......................................................9
Figure 4.7 Control Panel: Location of Centrifuge-On Button .................................................................10

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1 GENERAL
1.1 PURPOSE
1.1.1 The document outlines the procedure for cleaning centrifuge purification systems of the
type shown in Figure 3.1.
1.1.2 The control of coolant purity is an essential part of glass processing. Through typical
operations associated with fabricating elements, particulates resulting from glass
abrasion contaminate the coolant used in cutting and grinding. Such contamination can
have a significantly negative impact on workpiece quality, from increased levels of
roughness due to surface scratching. These problems can lead to production delays due
to time spent on reworks or locating replacements.
1.1.3 To minimize waste, maintain workpiece quality, and keep on schedule, a purification
system must be used to continuously process the coolant during production. Optical
Generating employs a centrifuge system that is sufficiently designed to meet workpiece
quality requirements. However, the system is successful only when regular maintenance
is performed to sustain peak efficiency; if not regularly cleaned, the centrifuge loses its
ability to remove particulates due to internal sludge build-up. Thus, maintenance of the
centrifuge has an important role in achieving the workpiece quality desired.
1.2 SCOPE
1.2.1 Although this document’s focus is on the equipment shown in Figure 3.1, the cleaning
procedure it outlines can be applied to any centrifuge with a removable basket liner (see
call out in Figure 3.2).

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2 RESPONSIBILITIES
2.1 TECHNICIAN
2.1.1 The cleaning of the centrifuge is tracked according to the time it was performed and the
person who performed it. For this reason, the technician is required to record his or her
signature, and date, on a log sheet maintained for the equipment.
2.1.2 The hinged cover on the centrifuge housing must be in a secure position before the
technician can perform any of the cleaning steps. A safety hook must be used as a
precaution against injury to arms or hands from a falling cover. The technician is not
permitted to use any means other than the safety hook for keeping the housing open.
2.2 MANAGEMENT
2.2.1 The management has the responsibility of ensuring personnel observe the above-
mentioned requirements, and that they follow all procedures as stated in this document.
If necessary, the manager or supervisor in Optical Generating should mandate training on
centrifuge maintenance for newly hired personnel.
2.2.2 The management must ensure that equipment has the tools required for carrying out
maintenance in a safe manner. When there is a risk of injury, the supervisor or manager
must not permit maintenance until the necessary tools are in place for eliminating the risk.
2.2.3 It is management’s responsibility to monitor the frequency of this procedure’s application.
The log sheets must be reviewed regularly to ensure the cleaning procedure is carried out
as instructed in this document.

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3 PROCESS DEFINITION
3.1 OVERVIEW
3.1.1 In general, milling machines require coolant for temperature control, and for washing away
particles from workpieces being ground or cut. After being cycled through the machines,
the coolant runs off the equipment work areas and then into a chiller. From the chiller, it
then flows into the collection tank for processing through the centrifuge system. The
centrifuge’s high-speed rotation separates the particulates from the pure coolant liquid.
Finally, the purified coolant is then recycled back to the machines.
3.1.2 In the centrifuge’s operation, a basket liner inside a rotor traps the glass particulates
suspended in the coolant. Over time, the particulates collected eventually form a layer of
sludge on the basket liner, which can affect the centrifuge’s efficiency. Therefore, a
regular cleaning of the basket liner is required to preserve the centrifuge’s normal
functioning. Without this regular cleaning, the sludge layer will continue to thicken on the
liner, causing increased levels of contamination in the recycled coolant.
3.1.3 To maintain the lowest possible levels of contamination, the Optical Generating
Department requires the centrifuge be cleaned twice a week to ensure the workpiece
quality desired.
3.2 CENTRIFUGE SYSTEM COMPONENTS
3.2.1 Figure 3.1 shows the centrifuge system as arranged on the Generating Department’s shop
floor. The coolant chiller is also shown.
Figure 3.1 View of Centrifugal Filtration System

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3.2.2 Figure 3.2 provides a close-up view of the centrifuge rotor. The rotor housing is open to
show the location of the sludge basket liner, which is a key component handled in the
cleaning operation discussed in this procedure. The figure also calls out the safety hook,
which securely holds open the hinged cover for maintenance operations.
Figure 3.2 The Centrifuge Rotor
3.2.3 To prevent injury, technicians must remember to use the safety hook for keeping the
hinged cover in an upright position, as shown above.

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4 REQUIRED STEPS
4.1 Power to the centrifuge rotor must be switched off before the housing is opened. Press the
CENTRIFUGE OFF button on the front panel, to deactivate the equipment (see Figure 4.1).
Figure 4.1 Control Panel: Location of Centrifuge-Off Button
4.2 Two valves must be closed to prevent coolant leaking back into the centrifuge:
4.2.1 Close the valve indicated in Figure 4.2, by turning the red lever.
Figure 4.2 Isolating the Centrifuge from Coolant Flow
4.2.2 Close the gray “T” valve mounted on the wall adjacent the centrifuge and chiller.
Although not shown directly, this valve’s general location is called out Figure 3.1.
Note: The above mentioned valves must remain closed throughout the entire
cleaning process. The valves are reopened only when the centrifuge is
completely closed and ready for operation.
4.3 Unlock the hinged cover of the centrifuge. Turning a knob on the top surface, at the edge
shown in Figure 4.3, unlocks the cover.

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Figure 4.3 Opening the Rotor Housing
Note: The above knob operates a screw for sealing the cover against the centrifuge
opening. A gasket underneath the cover creates the seal. When the knob is turned
the maximum distance outward, there will be an audible “click”, indicating that the
seal is broken. The housing is ready for opening after this sound.
4.4 Lift the cover off the centrifuge opening, and latch the raised end with the safety hook, as
shown in Figure 4.4. To latch, slip the loop over the thumbscrew (i.e., over the threaded
part emerging through the cover) and then secure the loop with the lug nut.
Figure 4.4 Cover Safety Hook
WARNING: DO NOT CLEAN THE CENTRIFUGE WITHOUT PROPERLY SECURING
THE COVER. Not using the safety hook introduces the risk of serious injury, as an
unlatched cover may fall on arms or hands.
4.5 Now unlock the rotor cover, by loosening four (4) bolts threaded into the flanged top, shown
in Figure 4.5. The bolts are very tightly threaded into the cover; use a suitably sized allen
wrench, or drive ratchet with an appropriately sized allen head, to loosen and unthread the
bolts in the CLOCKWISE direction.

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Figure 4.5 Bolt Locations on the Rotor Cover
WARNING: Splashing of coolant may occur from handling the rotor cover for removal.
Place a rag over the centrifuge opening for protection against exposure.
4.6 Using a crowbar, pry the rotor cover out of its seating in the centrifuge housing. To obtain
mechanical advantage, insert the crowbar’s tapered end between the centrifuge bowl and
the cover’s flanged end, as shown in Figure 4.6. When the flange is sufficiently raised for
handling, lift the rotor cover out of the centrifuge to expose the bowl, and the basket liner.
Figure 4.6 Removing the Rotor Cover from the Centrifuge Housing
4.7 By grabbing two handles at the top, lift the basket liner out of the centrifuge bowl, and carry
it to the sludge drum designated for hazardous waste. Dispose of the sludge cake (i.e., the
layer of glass particulates) collected in the basket.

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Note: The sludge drum is generally stored near a large coolant collection station in
the shop. An enclosed area, accessed only through a steel door, isolates both the
collection station and the drum from workshop areas.
4.8 Return the empty sludge basket to the centrifuge, inserting it back into the centrifuge bowl.
Then insert the rotor cover back over the centrifuge bowl. Make sure the cover is correctly
seated in the opening: gently tap on the flange surface with a rubber mallet, nudging the
cover into a tight fit.
4.9 Lock the rotor cover in the centrifuge, by threading and tightening the bolts removed in Step
4.5. Use an allen wrench or drive ratchet of the correct size. Place a rag over the
centrifuge opening to prevent exposure to splashing coolant.
4.10 Enclose the rotor, unlatching the hinged cover and locking the centrifuge housing: remove
the lug nut, seat the cover over the opening, and then turn the knob of Step 4.3 for a tight
seal. When not in use, the lug nut is placed on a magnetic strip attached to the equipment
framework.
This completes the procedure for cleaning the coolant purification centrifuge. Once
the hinged cover is closed, the centrifuge can be restored to normal operations.
4.11 Open the valves mentioned in Step 4.2, permitting coolant to flow through the centrifuge
system. Then, on the control panel, press the CENTRIFUGE ON button to restore the
normal operation of the system (see Figure 4.7).
Figure 4.7 Control Panel: Location of Centrifuge-On Button
4.12 Sign and date the cleaning log sheet for the centrifuge per Chapter 2.