Section 11365A
DEWATERING CENTRIFUGE - WESTFALIA
PART 1 - GENERAL
1.1 SCOPE
A. Work described in this
Specification section includes furnishing equipment, materials,
tools, incidentals and services required for a complete and
operable installation and performance testing of three (3)
horizontal decanter dewatering centrifuges, and control panels,
instrumentation, power panels, and related appurtenances. The
centrifuges shall be Westfalia Separator Model No. CA 1035-00-33.
B. All equipment shall be
installed, adjusted, performance tested, and placed in
operation in accordance with these Specifications, the
manufacturer’s recommendations, and as shown on the Drawings.
C. Equipment to be provided for each
centrifuge shall include, but not be limited to:
1. Solid bowl centrifuge.
2. Electric main motor drive.
3. Electric scroll motor drive.
4. External oil lubrication system
for rotating assembly’s main bearings.
5. Variable frequency drives with
harmonic mitigation.
6. Local centrifuge control panel
with I/O components, operator interface terminal
(OIT) and PLC.
7. All necessary sensors and
monitoring equipment.
8. All necessary vibration
isolators.
9. Centrate and dewatered sludge
chutes.
10. Density meters for feed
connection.
11. All flexible connections except
for electrical connections.
12. All necessary bolts, anchor bolts,
and hardware for centrifuge, lube oil unit, panels, and chutes.
13. Spare rotating assembly.
14. Spare parts and tools.
D. All equipment shall be
fabricated, assembled, erected, and placed in proper operating
condition in full conformity with the Drawings and Specifications,
engineering data, and instructions provided herein. The dewatering
centrifuge systems shall be specifically designed for the intended
conditions of service and materials shall be suitable for service
conditions described herein. All equipment shall be new and
shall be designed, fabricated, and assembled in accordance with
the best engineering and shop practices.
E. The installation of all materials
and equipment supplied herein shall be completed by the CONTRACTOR.
The Manufacturer shall be responsible for:
1. Design and fabrication of the
centrifuge equipment and integrated control system.
2. Conduct all shop, field, and
performance tests of equipment and integrated control system.
3. On-site advisory assistance
during installation of all centrifuge related equipment.
4. Start-up and training services
for all equipment supplied under this Specification section.
5. Eight months of on-site operations
and maintenance assistance services agreement (O&MASA),
providing the service of a qualified centrifuge manufacturer
representative to assist OCSD staff in process optimization and
routine maintenance of the dewatering centrifuges. The
manufacturer’s representative qualifications and role in the
O&MASA is discussed in PART 3 – EXECUTION of this
Specification section. The O&MASA shall extend for eight month
period following acceptance of the Reliability Acceptance Test (RAT)
as defined in Section 01810, Commissioning. The O&MASA
parameters shall be as follows:
a. The O&MASA shall be on
centrifuge manufacturer representative man-day basis and limited to
35 man-day worth of work in the eight month of the O&MASA
duration.
b. The service shall be scheduled by
OCSD’s staff and shall be one-half day minimum per visit and
limited to a total of 35 man-days total.
c. CONTRACTOR to pay the
manufacturer’s monthly invoices based on OCSD
approved time spent up to the 35
man-days.
d. Man-day is actual 8 hours worth
of work in Plant 1 and does not include travel time. Traveling cost
and living expenses for the manufacturer’s representative shall be
included in the man-day unit cost.
e. This O&MASA does not cover or
pay for any time spent on warranty issues throughout the warranty
period.
f. Manufacture’s representative
shall submit a report on the status and findings after each service
visit.
6. Submittal of all shop
drawings, certifications, Operation and Maintenance manuals,
warranties, etc as required in these Specifications.
1.2 RELATED SECTIONS
A. The requirements of the following
sections and divisions apply to the Work of this section. Other
sections and divisions of the Specifications, not referenced below,
shall also apply to the extent required for proper performance of
this Work.
1. Division 01, Additional General
Requirements
2. 01783, Vendor Equipment Manuals
3. 05505, Metal Fabrication
4. 09800, Protective Coating
5. 11005, Equipment: Basic
Requirements
6. 11121, Sludge Collection: Screw
Conveyors
7. 11341, Grinders
8. 11309, Progressing Cavity Pumps
9. 11369, Thickening Centrifuge
10. 16220, Electric Motors
11. 16419, Variable Frequency Drives
100 hp and Above
12. 16442, Control Panels
13. 17405, Process Instrumentation and
Control
14. 17410, Programming by Contractor
15. 17411, Programming by OCSD
1.3 DESIGN REQUIREMENTS AND
PERFORMANCE
A. All equipment and appurtenances
with the exception of the centrifuge control panels and motor
controller cabinets shall be suitable for exposure to splash and
spill conditions, and operation in continuous 95 percent relative
humidity conditions and in ambient air temperatures from 40 to 104
degrees F.
B. Centrifuge control panels and
motor controllers will be located in an electrical room provided
with conditioned air.
C. The units shall be capable of
continuous operation for 24 hours per day, seven days per week.
D. The centrifuges shall be capable of
dewatering sludge having the following characteristics:
1. Sludge Type: Municipal.
2. Sludge Composition: Digested
sludge that is a blend of primary sludge, waste activated sludge
(WAS), trickling filter sludge and surface waste (Nocardia waste
from aeration basins).
a. Primary sludge includes iron
salts used for enhanced solids removal from primary clarifiers.
3. Percent of total dry solids
contributed by each sludge stream (average):
a. Primary Sludge: 76 percent b.
WAS: 19 percent
c. Trickling Filter Sludge: 4
percent d. Surface Waste: 1 percent
4. Feed solids concentration:
a. Start-Up Conditions:
(1) Average: 2.0 percent
(2) Range: 1.7 percent to 2.3 percent
b. Long-Term Conditions (after
centrifuge thickening is fully operational): (1) Average: 3.5
percent
(2) Range: 3.0 percent to 4.0 percent
5. Feed sludge volatile solids
fraction:
a. Average: 58 percent
b. Range: 53 percent - 63 percent
E. The plant sludge characteristics
are highly variable. The Manufacturer recognizes the variability
of the sludge and the equipment supplied shall be suitable and
compatible with the Plant sludge under the range of sludge
characteristics described in this Specification.
F. The centrifuges shall be
optimized for dewatering with or without the continuous addition of
polymer as a conditioning chemical. In addition, the adjustable
pond setting dams may require changing for optimum process
capabilities.
G. A polymer chemical addition
conditioning system is being provided by the CONTRACTOR for chemical
conditioning of the raw solids prior to dewatering. The polymer
system is based on using bulk liquid mannich or emulsion polymers.
The centrifuge performance guarantee shall be based on this type of
system. The design parameters for the polymer system include:
1. Polymer Dosage Rate: 0 to 30
pounds (active polymer) per ton of dry solids
2. Polymer feed pumps, including
dilution water (per unit):
a. Capacity: 47 gpm
b. Secondary Dilution W ater:
Industrial (potable water after a backflow preventer) or recycled
water
3. Polymer Feed Concentration: 0.10
to 0.25 percent (including secondary dilution) H. Each centrifuge
shall be capable of the following performance for a minimum 45-day
continuous RAT testing:
1. All requirements listed in Table
1.
Table 1. Minimum Performance
Requirements
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Start-up
Average |
Start-up
Maximum |
Long-Term
Average |
Long-Term
Maximum |
|
Minimum Feed
Concentration, percent TSS |
|
|
|
|
|
Maximum Feed
Concentration, percent TSS |
|
|
|
|
|
Solids Throughputa, lb/hr |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Minimum Capturec, percent |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
a. Based on raw suspended
solids in raw f eed only.
b. M aximum polymer
dosage = 4 lb/dt x percent VSS f ract ion/1 0 c. The
percent solids capt ure shall be det ermined as f ollow s:
(QR)(SSR)-(QR+QP)(SSC)
Capture rate (%) = (Q )(SS )
x 100
R R
w here:
QR = f low rat e of raw
solids, gpm
QP = f low rat e of polymer
(including dilut ion w at er)
SSR = suspended solids cont ent
of raw solids f eed, mg/l
SSC = suspended solids
cont ent of cent rat e, mg/l
|
||||
2. Noise to be below 92 dBA for
all performance conditions and is not to be exceeded at any time
during testing.
3. Vibration to be below 10 mm/sec
RMS for all performance conditions and is not to be exceeded at any
time during testing (horizontal, vertical, and axial).
4. For the duration of the test,
dewatered solids concentration to be maintained above 25.
5. The minimum feed solids
concentration to be maintained for the duration of the test is 1.7
percent.
6. During the duration of the test,
the maximum polymer dose may not exceed 4.0 lb/dry ton for each 10
percent increase in volatile solids fraction (e.g., 23.6 lb per dry
ton if volatile solids fraction is 59 percent)
7. The type of polymer used during
the testing shall be jointly agreed to by the Manufacturer and the
ENGINEER. The polymer shall be readily available in
Southern California and shall have a unit cost per pound of active
polymer that is competitive with the unit cost of other polymers
used for municipal centrifuge dewatering applications in Southern
California.
8. Compliance with the thickened
sludge solids concentration, solids capture, and polymer dosage is
required for the range of feed solids concentrations above
(including minimum and maximum values).
1.4 SUBMITTALS
A. Submit drawings and equipment
data in accordance with Section 11005, Equipment: Basic
Requirements, and the following. All documents to be in English
or with all captions in foreign languages translated into English.
Documents with any un-translated captions will be automatically
rejected. Submit all required data for design of support
structures, piping system, electrical system, and instrumentation as
per the time frame defined in Division 1.
1. Equipment Data Sheet and detailed
shop drawings for all equipment supplied, providing dimensions,
gross and net weight, and minimum clearances.
2. G-volume calculations; provide
calculations based 1) bowl only and 2) bowl and cone.
3. Design Data for main drive,
bearings and lube oil unit heat exchanger.
4. Materials of
Construction/Abrasion Protection Features.
5. Anchor Bolts and Calculations
6. Vibration Isolator Detail
7. Standard Instruction Manual.
8. Detailed Centrifuge Installation
Instructions and details.
9. Part lists and bills of materials
of all equipment.
10. Proposed test procedures and test
reports for:
a. Laboratory testing of abrasion
resistant materials. b. Witness shop tests of centrifuges.
c. Field tests of centrifuges.
d. Performance tests of centrifuges.
11. Lubrication and Preventive
Maintenance Schedule.
12. Equipment Shipment, Storage,
Unloading, and Handling Instructions.
13. Field wiring diagrams and outline
drawings showing field wiring, requirements for conduit locations,
stub-ups, and physical sizing information. Physical location of the
electrical devices on the centrifuge and its ancillary equipment
should be shown on the Drawings, which shall be made specifically
for this Project. Wiring instructions shall be in English, NEMA
and ANSI standards shall be used for all electrical
connections.
14. Spare Parts and Special Tools
List.
15. Surface Preparation and Painting
Details.
16. Sample Factory Test Report.
17. Certification of calibration for
the shop test instruments and field test instruments.
18. Discharge Connection Details.
19. Electric Motor Submittal in
accordance with Section 16220, Electric Motors.
20. Control Panel Engineering
Submittal per the requirements of Section 17405, Process
Instrumentation and Control.
21. Sequence of Operations.
22. Vibration Monitor Details.
23. Variable Frequency Drive Submittal
in accordance with Section 16419, Variable
Frequency Drives 100 hp and Above.
24. Installation Plan and Performance
test procedures.
25. Process & Instrumentation
Diagrams, electrical diagrams, elementary diagrams, and control loop
drawings.
26. Warranties for the Work performed
under this Contract and, in particular, the wear and performance
guarantees.
27. Evidence of welder’s
qualifications.
28. Training lesson plan.
29. Test procedures for the Control
panels, VFDs, Motors and Centrifuge for different phases, including
FDT, ORT 1, 2, & 3, FAT and RAT per Section 01810, Commissioning
and 17405, Process Instrumentation and Control.
30. Test and gate reports as required
in Section 01810, Commissioning.
31. Programming submittals as required
in Section 17410, Programming.
B. For equipment or material for which
specific tests are not requested in this Specification, the
Manufacturer’s standard quality control test reports shall be
submitted. The tests shall have been performed not longer than three
(3) years before the date of submittal of the reports for
acceptance.
C. Six (6) sets of operation and
maintenance manuals and final As-built Drawings (Record Drawings) to
be provided at the completion of the job and in accordance with
Section 01783, Vendor Equipment Manuals. One (1) CD-ROM copy of the
O&M manual and drawings shall be provided in Adobe Acrobat
format.
1.5 QUALITY ASSURANCE
A. The centrifuge shall be the
product of manufacturers regularly engaged in the design,
fabrication, service, and repair of high-speed centrifuges. The
centrifuge shall be manufactured utilizing the latest manufacturing
machine tool technology. The bowl, scroll, rotating assembly, and
frame shall be manufactured to precise tolerances and shall with
readily interchangeable with those components of currently installed
models.
B. Certificate of Compliance: The
manufacturer shall warrant that the centrifuge shall be manufactured
in accordance with the Specifications.
C. All manufacturing facilities shall
be ISO 9001 certified for quality assurance in the design,
development, production, installation, and servicing of machines and
installations for mechanical separations.
D. The centrifuge manufacturer
shall have experience manufacturing decanter-type dewatering
centrifuges with bowl diameters of 30 inches or larger and operating
g-force in excess of 2,500 xg. The referenced installations
shall demonstrate a history of reliability and service consistent
with the OCSD’s expectations, specifically related to dewatered
solids concentration control. Provide a list of a minimum of four
(4) such installations with description, solids processing data,
contact names, addresses and telephone numbers with the bid
proposal. Failure of a referenced installation to meet these
criteria for performance, reliability, and service will be grounds
for excluding a manufacturer as an acceptable supplier.
E. The centrifuge and ancillary
equipment shall be designed and manufactured in accordance with
the following listed standards and specifications, including
applicable addenda in effect as of the date of bid submission. They
shall be considered an integral part of this Specification and shall
govern the design, fabrication, testing and inspection of equipment,
except as otherwise shown or specified herein:
1. American Gear Manufacturers
Association (AGMA)
2. American Welding Society (AWS)
D1.1-82, Structural Welding, and ASME Boilers and Pressure
Vessels
3. Deutsches Institute for Normal
Standards (DIN), if applicable
4. Verein Deutsche Inginieure (VDI),
if applicable
5. National Electrical Manufacturers
Association (NEMA)
6. Anti-Friction Bearing
Manufacturers Association (AFBMA)
7. American National Standards
Institute (ANSI)
8. National Fire Protection
Association (NFPA)
9. Joint Industrial Council (JIC)
10. American Society of Mechanical
Engineers (ASME)
11. Underwriters Laboratory (UL)
12. Institute of Electrical and
Electronics Engineers (IEEE)
13. American Society of Testing
Materials (ASTM)
14. American Institute of Steel
Construction (AISC)
F. Proof of qualification of the
technicians that the centrifuge manufacturer shall provide for the
installation, testing, and startup of the centrifuge assemblies,
shall be submitted to the ENGINEER for acceptance before the
installation is initiated. Welders shall have passed AWS
qualification tests or equivalent tests in countries other than the
United States such as DIN, within the last 12 months prior to the
time they are employed. Evidence of compliance shall be submitted to
the ENGINEER.
G. The manufacturer shall own and
operate at least one full service repair facility in the United
States, capable of performing all repairs on all portions of the
rotating assembly. The repair facility shall be capable of
performing balancing of all rotating components at the full
nameplate rpm of the rotating assembly. The Manufacturer shall
employ a minimum total of 20 Field Service and Process personnel
dedicated to centrifuge service and shall maintain a United States
based spare parts inventory in excess of five (5) million dollars.
1.6 EQUIPMENT GUARANTEES
A. Equipment Wear: The Manufacturer
shall furnish a guarantee for equipment wear based upon 10,000 hours
of operation for abrasion resistant protection system. The
equipment shall not exhibit a wear greater than 20 millimeter after
10,000 hours of operation. Warranty certificates in English, or
accompanied by certified translation, shall be submitted as part of
the shop drawing submittal. Manufacturer shall provide service and
materials to disassemble and inspect the supplied machine after
10,000 hours of operation or 24 months, whichever comes first. If
inspection reveals greater wear than guaranteed or damage of any
sort, Manufacturer shall repair as necessary.
B. The scrolls will bear a warranty
against faulty workmanship and design for 60 months starting at the
time of delivery. Normal wear and tear is excluded from the
scroll warranty.
PART 2 - PRODUCTS
2.1 GENERAL DESCRIPTION
A. The centrifuge shall be a
Westfalia Separator model number CA 1035. The centrifuge
shall be a solid bowl, horizontal, continuous feed, scroll
type unit. The centrifuge equipment shall be designed and built
to operate continuously or intermittently. The centrifuge shall be
designed for counter-current flow characteristics such that no
centrate tubes are required. The bowl/scroll design shall utilize
the conical section for optimal dewatering of the dewatered solids.
The dewatering centrifuge shall be able to separate at a G-force
between 2,000 and 2,700, corresponding to a speed range
between 1,200 – 2,150 rpm
B. Individual parts shall be
identical in design and workmanship and shall be
interchangeable with existing units
C. The centrifuge shall have a 316
stainless steel nameplate securely fastened to the base or other
visible location. The nameplate shall indicate the manufacturer’s
name, date manufactured and installed, model number and serial
number. Minimum size of the nameplate shall be 6 inches x 12
inches.
D. The centrifuge manufacturer shall
be responsible for providing a complete centrifuge system, as
described herein. The equipment shall be installed by the CONTRACTOR
who shall be responsible for off-loading the equipment, providing
any temporary storage, and installing the equipment in place.
Installation shall include mounting the unit, piping the unit,
providing power to the panels and all inter-connected wiring and
piping required between the various components.
E. Individual parts shall be
manufactured to standard sizes and gauges. Components of the
centrifuge shall be designed for the stresses, which may occur
during fabrication, shipping, erection or maintenance. Materials
shall be suitable for service conditions and as described herein.
The equipment shall be installed in a manner that prevents movement
between interconnecting structures, pipes, conduit, etc.
F. The dewatering centrifuge and
its components shall have the following nominal dimensions:
1. Rotating assembly 242 inches long
x 51 inches wide.
2. Frame assembly 232 inches long x
90.5 inches wide.
3. Motor assembly 100 inches long x
90.5 inches wide.
4. Overall centrifuge height of 130
inches.
5. Overall centrifuge length of 332
inches.
6. Overall centrifuge width of 90.5
inches.
7. All of the above components shall
be within the lifting capacity of a 20-ton bridge crane.
2.2 MATERIALS, FABRICATION, AND
FINISHING
A. All wetted parts of the
centrifuge rotating assembly shall be a minimum of 316 stainless
steel except for the “O” rings, seals, and abrasion-resistant
material. “O” rings shall be Viton rubber, lip type seals shall
be Viton. The feed tube, sludge feed pipe, solids discharge, and
liquid discharge compartments shall be constructed of 316
stainless steel. The frame and casing shall be fabricated of carbon
steel. All protective guards shall be constructed of painted carbon
steel. Fiberglass reinforced plastic covers shall not be allowed.
B. Design of all support
structures and bracing shall be in accordance with AISC
standard.
C. Structural steel shall conform to
ASTM Specification A36.
D. Welding shall conform to AWS
Structural Code D1.1-82 and, for special welding, ASME code for
Boiler and Pressure Vessels.
E. All carbon steel surfaces shall
be protected by a paint system specifically designed to resist
chipping, cracking, and lye or acid corrosion. The paint shall
consist of a two-part epoxy metal primer and a polyurethane finish
coat
F. All bolts, anchor bolts, hangers,
fasteners, and hardware for the centrifuge and associated equipment
shall be AISI Type 316 stainless steel
2.3 BOWL
A. The centrifuge bowl shall be 164
inches in length, with the inside diameter of 41 inches in the
cylindrical section, plus a conical beach extension. The bowl
shall be manufactured from centrifugal castings of duplex
stainless steel SAF 2205. All centrifugal cast material shall
be inspected for cracks, shrinkage, porosity, or other defects,
by means of a liquid dye penetrant test. The bowl shell shall be
designed to operate at a minimum force of 2700 x G. It shall be
subjected to a pressurization test to ensure the material is
structurally sound. Fabricated or statically cast bowl shells
shall not be allowed. Cylindrical and conical sections of the bowl
shall have a minimum thickness of 0.85 inch.
B. The front and rear bowl hubs
shall be centrifugally cast of duplex stainless steel Type SAF2205.
The pool depth in the bowl shall be adjustable by use of plate dams
at the large diameter end of the bowl. The bowl shell and extension
shall be ribs or grooves to trap a layer of solids between the bowl
wall and the conveyor.
C. The solids shall be conveyed up
the conical section of the bowl by the scroll rotating at a positive
differential speed. The solids shall be discharged from the bowl
via a series of circular discharge ports. Each port shall be
protected by a field replaceable tungsten carbide inserts. A
removable hood shall be provided so that the bushings are easily
inspected. The inserts shall be weight balanced in pairs.
2.4 SCROLL CONVEYOR
A. The centrifuge shall include a
horizontal scroll conveyor equipped with solid helical flights and
independently mounted concentrically within the centrifuge bowl.
The scroll shall utilize a differential speed which is greater than
the bowl speed to convey solids from the cylindrical section to the
conical section and out of the bowl with a minimum disturbance to
the pool. The scroll shall be manufactured from duplex stainless
steel Type SAF 2205 and shall contain a feed compartment designed
for the gradual acceleration and low velocity introduction of feed
to the centrifuge bowl. Provisions shall be made for introduction
of polymer inside this feed compartment. The edge and the face of
the conveyor flights shall be protected by a series of sintered
tungsten carbide tiles beginning one wrap before the feed zone and
ending at the solids discharge. The remainder of the flights shall
be protected by flame sprayed tungsten carbide on the edge of the
face of the conveyor.
2.5 BEARINGS
A. The centrifuges shall be designed
so that the entire rotating assembly is supported by two main pillow
block bearings. Each main bearing shall be forced oil lubricated
ball or cylindrical roller type bearing. Bearings for the scroll
shall be permanently grease lubricated with lithium-saponified
grease. The bearings shall have a minimum L10 lifetime rating
of 100,000 hours.
B. The main bearings shall be
equipped with RTD type temperature sensors which monitor the
temperature of the bearing race directly. The sensors shall be
platinum ohm resistance type PT100. Monitoring of the oil
temperature shall not be an acceptable method of protection for the
bearings
2.6 FRAME AND CASING
A. The rotating assembly and
bearings of the centrifuge shall rest on a carbon steel frame
specifically designed for rigidity and noise reduction. Frames
containing concrete shall not be allowed. Frame and casing shall be
painted with a lye, acid, and impact resistant two-part epoxy resin
paint. The stainless steel case shall be designed to act as a
protective guard and to provide a complete enclosure for odor
containment. All wetted parts are to be 316 stainless steel. The
product collection chambers shall be stainless steel with flanges
for the dewatered sludge and centrate discharge. The sub-frame and
legs shall be constructed of tubular steel. The bowl cover shall
be stainless steel. Fiberglass reinforced plastic covers shall not
be allowed.
2.7 DRIVE SYSTEMS
A. Main Drive System:
1. The bowl drive system shall
consist of a 500 hp electric motor and a belt drive system. The
belt drive system shall consist of individual V-belts to provide
full load capacity and to withstand the full starting torque of
the system with a variable frequency drive (VFD). Refer to
Section 16419, Variable Frequency Drives 100 hp and Above, for VFD
requirements and manufacturers.
2. The main motor shall be a
squirrel cage induction motor and shall be provided with thermal
protection. The motor shall have copper windings and be of a high
thermal capacity design for operation of 460 V / 3Ø / 60 Hz power.
The motor temperature shall not exceed 130 degrees C at 90 percent
nameplate voltage. The noise level shall not exceed 85 dbA sound
pressure measured at 3 feet from the motor in all directions. For
additional motor requirements, refer to Section 16220, Electric
Motors.
3. With the motor at ambient
temperature, it shall be capable of making two (2) complete starts
in succession with coasting to rest between starts. The motor shall
also be capable of at least one restart within one hour after any
shutdown. The motor bearings shall be grease lubricated, ball or
roller anti-friction type of standard manufacture. The bearings
shall be conservatively designed to withstand all stresses of the
service specified.
B. Scroll Drive System:
1. The differential motor provides
torque overload protection for the scroll and gearbox without
the need for mechanical devices such as shear pins. Each
centrifuge shall be equipped with a two stage planetary gear reducer
unit which shall control the differential speed between the
centrifuge bowl and conveyor. The gear unit shall have a torque
capacity of at least 500,000 inch pounds as required to meet the
specified service conditions. Gears shall meet AGMA Class 10 and
11 requirements. Lubrication is self-contained using high
performance gear oil. The gear box shall be independently balanced
from the centrifuge. Each gear unit shall be protected from
damage due to high torque overload. A thermal overload
protection system on the drive motor shall not be considered as
providing sufficient protection for the gear unit. The cyclogear
drive units will not be acceptable.
2. The differential motor is a 125
hp 1800 RPM motor mounted on the motor frame below the main drive
motor. The differential motor turns the input shaft of the gear via
v-belts and shall be driven by VFD. The system shall be designed
such that the differential scroll speed is 1 -- 6 revolution per
minute (RPM) during normal operating conditions. The motor shall
have copper windings and be of a high thermal capacity design for
operation of 460 V / 3Ø / 60 Hz power. For additional motor
requirements, refer to Section 16220, Electric Motors. For VFD
requirements, refer to Section
16419, Variable Frequency Drives 100
hp and Above.
3. The torque overload protection
feature functions by reading the amperage draw of the differential
motor and tripping an alarm upon reaching a two stage set point. The
first stage set point will signal the control system to shut off the
sludge feed and begin flushing the centrifuge. The second stage set
point shall shut down the main motor.
2.8 NOISE AND VIBRATION
A. The centrifuge shall be
designed such that the average free field noise level
measured at three (3) feet around the periphery of the complete
centrifuge assembly shall not exceed 92 dbA when tested at the
manufacturing facility without feed and with the inlet and
discharges closed.
B. The centrifuge, when running
without feed, shall be measured for vibration in the manufacturing
facility. The vibration velocity shall be less than 10.0
mm/s when measured under dry shop test conditions.
C. Vibration Isolators:
1. The centrifuge shall be mounted
on visco-elastic type vibration isolators. The number and
vibration constant of the isolator shall be as recommended by the
isolator manufacturer for the load and impact resulting from the
operation of the centrifuge. The isolators shall be capable of
dampening vibration in all directions created during normal
centrifuge operation.
2. There shall be no rigid
connections at the feed tube, vents, solids discharge, liquid
discharge or other components whatsoever to the machine, thus
preventing transmission of vibration to structure, piping and
appurtenant equipment.
D. Flexible Connectors:
1. To insure a quiet installation,
flexible connectors shall be provided by the Manufacturer to isolate
the centrifuge from the building structure. Stainless steel chutes
shall be provided to transition from rectangular discharge to
circular piping. The solids and centrate chutes shall be equipped
with rubber isolators with 316 stainless steel backup flanges.
All hardware shall be supplied by the CONTRACTOR. Flexible pipe
connections shall be supplied for the sludge feed line, polymer
feed, centrate discharge, wash water feed, lube oil lines and
chutes. All flexible connections shall be flanged for simple
connection to associated piping.
2. Due to local conditions, flexible
connectors for the main drive motor, scroll drive motor and
centrifuge junction boxes shall be furnished by the CONTRACTOR, such
that all local electrical codes are met.
E. Centrate and Solids Chutes:
1. The manufacturer shall supply
chutes to be mounted below the discharge of the frame, as shown on
the Drawings. All chutes to be fabricated from 1/8 inch thick 316
L stainless steel plate. Chutes and
supports to confirm to Section 05505, Metal
Fabrications. F. Inlet Manifold:
1. The manufacturer shall supply the
inlet manifold for each centrifuge assembly, which shall combine and
direct into the centrifuge the sludge feed, polymer feed, and wash
water feed. Final arrangement of the inlet manifold should match
the process Drawings provided. The manifold shall be manufactured of
316 stainless steel.
G. Vibration Monitoring
1. The centrifuge shall be equipped
with vibration monitoring system consisting of an accelerometer,
digital display, 4-20 mA output, alert alarm and danger alarm for
each input point.
2. Upon reaching an alert (stage 1)
alarm, the control system will issue a warning alarm at the panel.
Upon reaching a danger alarm (stage 2), the control system will shut
down the centrifuge in a controlled shut down sequence.
3. The vibration monitor shall
be equipped with the following outputs to the centrifuge PLC:
a. Analog Input (AI) to the PLC:
1) Liquid side vertical vibration.
2) Liquid side horizontal vibration.
3) Solids side vertical vibration.
4) Solids side horizontal vibration.
4. The vibration monitor shall
be Bentley Nevada 3500 Series, Rockwell
Automation, Or Equal.
2.9 LUBRICATION
A. The two main pillow block
bearings on the centrifuge shall be lubricated by separate forced
oil lubrication systems. The scroll bearings shall be permanently
grease lubricated with a lithium saponified grease. The gears shall
be oil filled with suitable gear oil. Each oil lubrication system
shall consist of the following:
1. 15 gallon oil reservoir.
2. Circulation pump, 5 hp.
3. Oil return flow sensors.
4. Oil reservoir level switch.
5. Water-to-oil heat exchanger.
6. Sight gauge.
7. Temperature indicators.
8. Oil filter.
9. Oil pressure relief valve.
10. Oil pressure supply and return
hoses.
11. Instrumentation junction box.
2.10 GUARDS
A. Guards for all gearboxes and belt
drives shall be a minimum 0.11 inch 316 stainless steel and shall be
designed to OSHA standards. Completely enclose the entire belt drive
system and construct to minimize vibration. Guards manufactured
from fiberglass reinforced plastic shall not be allowed.
2.11 ANCHOR BOLTS
A. Anchor bolts shall be supplied by
the installing CONTRACTOR and be constructed of
316stainless steel.
B. CONTRACTOR shall determine anchor
bolt sizing.
C. Provide structural calculations
for the required force level for each component. a. Use seismic
design criteria listed in Section 01332.
b. Provide summary of loads to each
anchor.
c. Structural calculations shall be
signed and sealed by a professional Structural
Engineer registered in the State of
California. d. Number calculation pages.
2.12 CENTRIFUGE BOWL TRUCK
A. The manufacturer shall supply one
(1) cart for moving the rotating assembly and scroll within the
Thickening and Dewatering Facility.
2.13 PAINTING
A. Provide the protective coating of
all indicated surfaces including surface preparation, pretreatment,
coating application (including primer, intermediate and finish),
protection of surfaces not to be coated, and all appurtenant Work.
B. The following surfaces shall not
be protective coated hereunder unless indicated.
1. Stainless steel.
2. Machined surfaces.
3. Grease fittings.
4. Glass.
5. Equipment nameplates.
C. Coating system shall comply with
state and local regulations.
D. Definitions: The terms "paint,"
"coatings," and "finishes" as used herein, shall
mean surface treatments, emulsions, enamels, paints, epoxy resins,
and all other protective coatings, except galvanizing or
anodizing, whether used as a pretreatment, primer, intermediate
coat, or finish coat. The term "DFT" means minimum dry
film thickness.
E. The manufacturer shall use
coating materials suitable for the intended use and recommended by
the coating manufacturer for the intended service.
F. Protective Coating Materials:
Products shall be standard products produced by recognized
manufacturers who are regularly engaged in production of such
materials for essentially identical service conditions.
G. Coating System - Inorganic
Zinc/Polyurethane: The inorganic zinc primer shall be a water or
solvent based, self-curing, zinc silicate 2-component inorganic
coating which contains at least 85 percent of metallic zinc by
weight in the dried film, and is recommended by the coating
manufacturer as a primer for this system. The intermediate coat
shall be a high-build two component epoxy with a solids content of
at least 70 percent by volume. Finish coats shall be a 2-component
aliphatic acrylic or polyester polyurethane coating material that
provides superior color and gloss retention, resistance to chemical
fumes and severe weathering, and a minimum solids content of 58
percent by volume.
1. Prime coat (DFT = 2 mil),
Dimetcote 12, Carbozinc 11 HS, Tnemec 90-92, Or
Equal.
2. Intermediate coat (DFT = 4 mils),
Ameron 400, Carboline 893, Tnemec 104, Or
Equal.
3. Finish coats (one or more, DFT =
3 mils), Amershield, Carboline D134 HS, Tnemec 73, Or Equal.
4. Total system DFT = 9 mils.
5. Intermediate coat shall be
applied in excess of 4 mils DFT or in more than one coat as
necessary to completely cover the inorganic zinc primer and prevent
application bubbling of the polyurethane finish coat.
6. More than one finish coat shall
be applied as necessary to produce a finish with uniform color and
texture.
7. Coating manufacturers and paint
numbers are listed to show type and quality of coatings.
2.14 MISCELLANEOUS
A. Seal water, cooling water,
sample gauges, and valves to be supplied by the
CONTRACTOR as indicated on the process
and plumbing Drawings
2.15 SPARE ROTATING ASSEMBLY
A. Provide one spare rotating
assembly for the dewatering centrifuges.
B. The spare rotating assembly shall
be manufactured and tested in the same manner as the rotating
assemblies for the installed unit. The rotating assembly shall be
factory tested in one of the dewatering centrifuges supplied for
this Project.
C. The spare rotating assembly will
be stored on the main centrifuge floor at Plant 1. CONTRACTOR shall
supply stationary oak cradles or similar support structures
to reliably support the entire rotating assembly. Support system
shall allow access to the rotating assembly for all maintenance
activities including periodic rotation of the equipment.
2.16 STANDARD TOOLS, SPARE PARTS,
AND ACCESSORIES
A. Manufacturer shall supply all
tools, (if not already supplied with thickening centrifuge)
supplies, spare parts, and special equipment as described in
Schedule 11365-1 and below.
B. Provide one year’s supply of
all lubricating oils and greases recommended by the manufacturers,
and as per accepted shop drawings, for all components for a
continuously operating machine.
C. Provide one year’s supply of
filter elements for the lube oil unit, based upon manufacturer’s
recommended replacement intervals for a continuously operating
machine.
D. Spare parts shall be identical and
interchangeable with the original parts and marked with their
respective part numbers.
-
Schedule 11365-1Dewatering CentrifugeTools, Supplies, Spare Parts and Special Equipment for Westfalia Unit
Minimum Requirements
ItemNo.
Description of Item
Quantity
Tools
1
Set of Special Tools for Centrifuge Maintenance
1
2
Bowl Lifter
1
3
Conveyor Extracting Tools
1
4
Torque Wrench
1
5
Bearing Puller
1
6
Pillow Block Lifting Eyebolts
1
7
Pillow Block Bearing Remover
1
8
Pillow Block Dowell Pin Remover
1
9
Seal Holder Puller
1
10
Gearbox Adaptor Removal Aid Kit
1
Supplies
11
One Years Supply of Centrifuge Lubricants
1
Spare Parts
Grease Lubrication System
12
Grease Lubrication System Complete
1
Wear Protection
13
Set of Solids Discharge Bushings
3
14
Set of Solids Discharge housing Wear Plates
3
Bearings
15
Set of Main Bearing
2
16
Set of Scroll Conveyor Bearing
2
17
Set of Miscellaneous Bearings
1
-
Gaskets
18
Set of Gaskets (rotating assembly)
3
19
Set of Gaskets (frame)
3
Miscellaneous
20
Set of V-belts
2
21
Set of Nuts/Bolt/Washers(10 of each size)
1
22
Scroll Conveyor Tiles
40
2.17 INSTRUMENTATION AND CONTROLS
A. General:
1. The centrifuge control system
shall have a PLC with an Operator Interface Terminal (OIT). The
control system shall be designed to work in manual and automatic
modes. Should a disruption occur, the centrifuge monitoring system
shall indicate the cause with a first out sequence and define the
fault.
B. Centrifuge Control Panel:
1. NEMA12 free-standing enclosure.
The Centrifuge Control Panel design shall be as indicated in the
instrumentation Drawings. A Modicon Quantum PLC shall be supplied
and programmed to operate the necessary sequences. The PLC supplied
shall be as specified in Section 17405, Process Instrumentation and
Control, and shall be programmed per OCSD standards and as defined
in Section 17410, Programming by Contractor. Included shall be a
centrifuge automatic torque control module that shall maintain
process optimization within adjustable preset limitations and
operate in differential speed and torque modes. Included in the
front door shall be an E-stop pushbutton, an alarm acknowledge
pushbutton, an alarm silence pushbutton, and alarm horn. All
pushbuttons and pilot lights shall be water tight and corrosion
resistant. The OIT shall be utilized for major operational
adjustments. The panel will house the PLC and industrial hardware
components. All field wiring labeling shall be per OCSD
standards.
2. All components in the control
panel shall be completely factory wired. All external control
connection points shall terminate on a terminal strip. There shall
be a minimum of 10 percent spare terminal connections supplied. The
PLC shall be capable of interfacing via Ethernet, to the Plant SCADA
system. The OIT shall display Centrifuge monitoring and control
information including alarms and events with actual time and date.
C. Centrifuge Power Equipment:
1. Separate VFDs shall be provided
for each of the main drive and scroll drive motors. The lube pump
motor starter shall be mounted in the MCC provided by the
CONTRACTOR.
D. Field Instruments:
1. Vibration Monitoring System:
a. Function: Vibration monitoring of
rotating machinery. b. Style: 19 inches EIA rack.
c. Power Input to Rack: 120 VAC. 60
Hz.
d. Power Supply Module: Shall
produce output to transducers: -24 VDC+0 percent, -2.5 percent;
transducer voltages shall be overload protected per channel on
the individual monitor circuit boards.
e. Temperature Range: Operating: +32
to +150 degrees F; Storage: -40 to
+185 degrees F.
f. Relative Humidity: 95 percent
max. non-condensing. g. Rack Housing Rating: Weatherproof.
h. System Monitor Module: Shall
monitor all rack power supply voltages. Shall include front panel
push buttons to adjust alarm set points for any monitor on the rack;
alarm reset switch. Terminals shall be available in the rear signal
input module for connection of contact closures inputs from remote
locations.
i. There shall be two alarms (alert
and danger) 1 per channel for each type of module. Dual epoxy-sealed
relay modules sha1l be furnished with each module. All relays shall
include arc suppressors. Contact rating shall be 5A @ 120 VAC.
Contact life shall be 10,000 cycles minimum at rated load.
j. Vibration Monitoring Modules:
Refer to Paragraph 2.8.G above.
2. Frequency Current Converter:
a. Centrifuge bowl and speed sensors
shall be provided to monitor speed. The control module shall
transmit a current output proportional to an input frequency.
b. Key features shall include:
1) 120 VAC supply voltage.
2) Adjustable input frequency range
of .001 Hz to 999 Hz.
3) 4-20 mA output signal.
c. Units shall be Pepperl and Fuchs
Model WEM/EX-FSU, Or Equal.
3. Suspended Solids Concentration
Analyzer:
a. The Suspended Solids analyzer
shall be microprocessor-based and directly accept a suspended solids
concentration sensor manufactured by the analyzer manufacturer. The
analyzer shall be as specified in Section 17405, Process
Instrumentation and Control.
2.18 SEQUENCE OF OPERATIONS
The following pages describe the
Control Strategies to be implemented by the
Manufacturer under this Division.
A. General:
1. The Control Strategy provided
herein is subject to revisions during the shop drawing phase of the
Contract. The Centrifuge manufacturer shall submit a control
strategy for the Control of the Dewatering Centrifuges furnished
under this Contract. The OCSD reserve the right to make changes to
the basic control strategy described below during shop drawing
review. A minimum of Ten (10) days on site engineering shall be
provided by the Centrifuge manufacturer for making changes to the
Control strategy, process optimization, and coordinating with the
OCSD's auxiliary control system. The cost of providing this service
shall be included in the Centrifuge Manufacturer's Lump sum price
for this Contract as indicated in the Bid Documents.
2. The Dewatering Centrifuges shall
operate with minimal operator intervention. The START sequence shall
be initiated either from a Centrifuge LOCAL control Panel or from
the OCSD's REMOTE control workstation. The selection of LOCAL or
REMOTE control shall be made at the Centrifuge LOCAL control Panel
OIT. Under alarm or "EMERGENCY STOP" conditions, the
shutdown sequence shall be automatically triggered.
B. Auto Mode:
1. Start up Sequence:
a. The Centrifuge control system
shall verify that no fault conditions exist, and that all
centrifuge system permissives have been met including all
auxiliary systems permissives.
b. The START sequence shall be
initiated by the operator from the Centrifuge LOCAL control panel
operator interface or REMOTE operator workstation depending on the
MODE selected at the LOCAL control panel or from any location with
proper password authority.
c. The pre-lube system shall engage
for a predetermined time period. After the pre-lube cycle is
finished, the main motor shall start, and the bowl and scroll begin
to rotate. The main motor shall be ramped up to the preset speed.
The preset speed shall be set at the Centrifuge Control Panel; this
setting shall be password protected to prevent unauthorized changes.
The ramp-up time shall be determined by the manufacturer. The
ramp-up time shall be adjustable with an initial setting of 30
minutes. During this start cycle, the scroll shall convey any
remaining solids out of the bowl before the bowl full speed setting
is reached. The Centrifuge panel PLC shall continuously monitor all
interlocks and fault conditions.
2. Alarms/Interlocks:
a. Note: The Centrifuge manufacturer
shall determine the vibration monitoring system delay time for run
up. This will prevent nuisance vibration trips during startup with
unequal sludge on the rotating assembly. Below is a partial list of
alarms. Alarms shall be provided as shown on the P&IDs.
1) Main motor VFD fault.
2) Main motor winding temperature
High.
3) Main motor Circuit Breaker Trip.
4) Scroll motor VFD fault.
5) Scroll motor winding temperature
High.
6) Scroll motor Circuit Breaker Trip
7) Any of the two Lube oil pump not
running (overload trip or any other reason).
8) Torque alarm HI.
9) Torque alarm HI HI.
10) Solids side bearing temp HI.
11) Solids side bearing temperature HI
HI.
12) Liquid side bearing temperature
HI.
13) Liquid side bearing temperature HI
HI.
14) Vibration alarm HI.
15) Vibration alarm HI HI.
b. If any of these conditions are
present, the centrifuge shall not start. If the HI HI conditions are
reached during the operation, the centrifuge shall shut down. Once
the centrifuge reaches full speed, a feed permissive (READY for
Sludge) shall be set in the Centrifuge PLC. This permissive shall be
transmitted to the Dewatering PLC as a hard wired normally open
contact. The normally open contact shall close when the Centrifuge
is ready to accept sludge feed. This permissive will allow the
auxiliary system equipment associated with the sludge feed system
(i.e. polymer system, sludge feed) to RUN.
c. Each of the three dewatering
centrifuges discharge directly into their respective classifiers
located directly beneath the centrifuge. The centrifuge PLC shall
provide another normally open discrete output hardwired to the
Dewatering PLC that should close to run the classifier in the
forward direction as the centrifuge starts to produce cake.
d. The sludge feed rate shall
be determined by the operator based upon predetermined criteria
including:
1) Sludge feed percent
concentration.
2) Centrifuge sludge discharge
desired concentration. C. Polymer Feed Pumps:
1. Polymer is delivered to the
Centrifuge from the Polymer Mix/Aging System via a
Polymer feed pump tied directly into
the sludge feed line to each Centrifuge.
2. The sludge feed flow rate input
signal to the Centrifuge PLC is wired directly to the centrifuge
control panel PLC from the sludge flow meter.
3. Centrifuge System Control:
4. Scroll drive system of
dewatering centrifuge will provide automatic speed variation
between the scroll and the bowl based on torque. The scroll drive
system shall provide for the automatic, torque-controlled regulation
of relative scroll speed, corresponding to changes in feed
concentration or quality, in order to continuously maximize cake
solids concentration. Torque monitoring shall consist of an alert
limit and alarm limit. The alert limit shall shut down the sludge
feed pumps. The alarm limit shall shut down the centrifuge. In
addition, appropriate adjustments to the centrifuge operating speed
(manual adjustment by centrifuge manufacturer) polymer dosing, etc.
shall be made based on Centrifuge Discharge Solids Concentration by
the Centrifuge Manufacturer to optimize the operation of the
Centrifuge.
D. Shutdown Sequence:
1. The shutdown sequence shall be
initiated by the operator by selection of “AUTO SHUTDOWN” at
either the LOCAL centrifuge panel operator interface or at the
OCSD’s REMOTE workstations. In addition, any of the faults
indicated previously shall trigger an auto shutdown sequence. The
Centrifuge PLC shall remove the sludge feed permissive to the
Dewatering PLC which shall result in a shutdown of the feed systems.
The polymer system and sludge feed pump will shut down. The flush
water comes on at 400 gpm and below as the sludge feed begins to
stop. The purpose of the dilution water is to prevent the sludge
from dewatering. The main motor then cuts off and the Clean-in-Place
(CIP) sequence starts.
E. Emergency Shutdown:
1. The Emergency shutdown (initiated
either by the E-stop push button (Maintained mushroom head type) at
the Centrifuge LOCAL panel; the E-stop near the lube pumps; the
E-stop at the centrifuge; the E-stop at the main drive or scroll
drive VFDs; or by system alarms/interlocks) shall shutdown all
pieces of equipment. The alarms and shutdown shall follow the
shutdown sequence. Upon clearance of the alarm conditions or
resetting of the E-STOP push button, the system can be restarted.
|
Alarm Condition |
Action |
|
|
Alarm at Local panel and Remote workstations. No other action. |
|
|
Controlled shutdown initiated. Operator acknowledges alarm. |
|
|
– Alarm at local panel and Remote
workstations – Operator acknowledge alarms – Feed system
given signal to stop – Bowl flushing sequence starts – When
condition clears, bowl flushing stops, and
feed system given OK to start |
|
|
– Initiates controlled shutdown sequence – Alarm at local
panel and remote workstations – Operator acknowledges alarm |
|
|
– Sends signal to Stop feed system – Alarm at local panel
and remote workstations – Bowl flush sequence starts |
|
|
– Alarm at local and remote workstations – Emergency
shutdown sequence initiated – Operator acknowledges alarm |
|
|
– Alarm at local and remote workstations – Controlled
shutdown initiated |
|
|
– Controlled shutdown sequence initiated – Alarm at local
and remote workstations |
|
|
– Controlled shutdown sequence initiated – Alarm at local
and remote workstations |
|
|
– Centrifuge placed in idle mode – Alarm at local and
remote workstations |
|
High percent solids or failure of percent solids analyzer at
Centrifuge solids discharge |
|
F. System Maintenance Mode:
1. The system maintenance mode
shall be designed to allow the operator to operate the
centrifuge without initiating the polymer and sludge feed systems.
It shall be intended for troubleshooting purposes only. The system
shall not be operated in this manner when processing sludge. The
feed system (polymer and sludge shall also shut down and will not be
allowed to start).
2.19 OPERATOR INTERFACE TERMINAL
(OIT)
A. The unit shall be located on the
front of the Centrifuge Control Panel front face and be setup to
display information graphically and provide control graphics to
completely control the Centrifuge system.
B. Unit shall be Magelis Compact iPC,
Maple Systems, Or Equal. C. Display:
1. Display Size: 15 inch.
2. Operator Input: Touch Screen.
3. Real Time Clock: Battery backed
clock time stamps for alarm data.
4. Resolution: XGA 1024 x 768.
5. Application Memory: 2GB.
6. Communication Ports: Ethernet,
USB, RS-232.
7. Programming: Vijeo Citect
Designer.
8. Input Voltage: 120 volt, AC.
9. Storage: 40 GB Hard Drive. D.
Environmental:
1. Operating Temperature: 32 degrees
to 131 degrees F.
2. Storage Temperature: -13 degrees
to 158 degrees F.
PART 3 - EXECUTION
3.1 GENERAL
A. The manufacturer is
responsible for all aspects of the centrifuge system, with the
exception of the installation of the major components and external
wiring. All internal wiring and skid-mounted wiring required in the
shop shall be the responsibility of the Manufacturer.
Responsibilities include design and fabrication, shop performance
tests, safe delivery to the site, check out the installation by the
CONTRACTOR, field checkout tests, field performance tests, equipment
startup services, furnishing all tools, supplies, spare parts, and
special equipment, and proper training of OCSD personnel.
3.2 FACTORY/SHOP TESTING
A. Factory testing of the centrifuge
shall be performed at the centrifuge manufacturer’s facility to
demonstrate the absence of mechanical or electrical defects and that
the centrifuge operates within the specified limits. Equipment to be
shop tested including the centrifuge, main drive motor, control
panels, and VFDs. Factory testing of the control panels and VFDs
shall be performed independently at the respective locations of
manufacture. Test requirements for control and drive panels are in
Division 17.
B. Shop Testing Procedure:
1. Centrifuge manufacturer shall
allow inspection and witness of the shop test of the equipment by
the ENGINEER. In case of a failure of a test and
consequent necessity to repeat the test, all related expenses shall
be borne by the CONTRACTOR.
2. Equipment to be shop tested and
witnessed by the ENGINEER shall include:
a. Centrifuge.
b. Control Panels. c. VFDs.
3. Centrifuge manufacturer shall
notify ENGINEER of the test schedule not less than 14 days in
advance.
4. Test Conditions:
a. The following tests shall be
completed before the centrifuge is released for shipment. Testing
shall consist of a four hour dry run followed by a two hour wet run.
During the test the machine shall be run at maximum, minimum, and 3
rpm differential speeds. Shop testing shall meet the tolerances in
the Article 1.3 of this Specification before shipping and delivery.
1) Vibration measurement with bowl
empty.
2) Vibration measurement with bowl
filled with water.
3) Operation of machine for 2 hours
with water.
4) Motor starting amperage.
5) Test equipment/procedures:
i. Test equipment shall be
calibrated.
ii. Unit shall be tested with a
simulation panel.
6) In a separate shop test, all
circuits on the control system panel shall be checked and all alarms
and shutdown conditions simulated to check the alarm circuits.
5. Certified test results shall be
submitted after completion and prior to shipping and delivery.
6. Shop testing shall include
testing of the spare rotating assembly which shall be placed in one
of the frames of the other machines for testing purposes.
3.3 SHIPMENT AND DELIVERY TO SITE
A. The manufacturer is responsible
for shipment and delivery of the equipment as described in the
General Requirements. The manufacturer shall coordinate with the
installation CONTRACTOR as needed to allow effective delivery to the
area of work. each centrifuge shall be delivered as 7 separate
pieces – rotating assembly, frame, casing, motor, VFDs, panels,
and chute plus miscellaneous minor shipments of ancillary equipment,
tools and spare parts.
3.4 INSTALLATION REQUIREMENTS
A. The Manufacturer shall provide
written guidance and on-site advisory assistance in the installation
of all equipment supplied herein.
1. Submit detailed instructions on
preparation and installation of the centrifuge assemblies.
Provide technical assistance to the ENGINEER as requested to clarify
or expand information as needed.
2. Observe installation
CONTRACTOR during unloading of the centrifuge assembly.
Inform the installation CONTRACTOR in method of storage and notify
when storage does not conform to manufacturer’s requirements.
Provide all necessary maintenance on centrifuge assemblies during
period of storage.
3. Provide technical assistance to
the installation CONTRACTOR.
4. Additional polymer injection point
will be provided by the installation CONTRACTOR during installation.
The manufacturer shall verify that the proposed location and
arrangement of the additional injection point is acceptable for
proper performance of the centrifuge. Proposed injection points will
be the same as current.
5. Coordinate with the installation
CONTRACTOR to arrange a mutually acceptable schedule to ensure
substantial and final completion of special services consistent with
the construction completion dates.
3.5 MAINTENANCE OF INSTALLED
EQUIPMENT, GATES AND VALVES
A. Maintain the operability and
functionality of all installed equipment, gates and valves between
the time of installation and the commissioning period. See
Specification section
01660, Shipping, Storage and Handling
Requirements, for requirements.
3.6 FIELD MECHANICAL TESTING
A. The manufacturer shall conduct
field testing of the centrifuge to confirm all equipment is properly
installed and ready for operation and to demonstrate:
1. The equipment was not damaged
during storage, transportation, or installation.
2. The equipment is properly
installed and aligned
3. There are no mechanical defects
in any parts.
4. The equipment is free of
overheating, objectionable vibration, and overloading. The
centrifuges and ancillary equipment shall operate without
overheating, overloading of any parts or systems, and within the
specified limits of vibrations, noise, temperature, pressures, and
torque.
5. The proper interaction and
effective control of the centrifuge, drive motor, scroll drive,
lubrication system, and control panel, and drive panel will also be
demonstrated, including all interlocks, safeties, and controls
function as intended.
6. That the centrifuges can operate
without problems within the specified limits of solids feed and
polymer feed flow rates producing dewatered sludge of the specified
consistency.
B. The test procedure, submitted by
the manufacturer and accepted by the ENGINEER, shall be run by a
qualified representative of the centrifuge manufacturer in the
presence of the OCSD staff and the ENGINEER.
C. The field tests shall consist of:
1. Preliminary testing of control
circuits, shutdowns, and control loops to verify correct
interconnecting wiring to alarms by opening various field device
contacts at the device and verifying loss of continuity at the
appropriate control panel terminals
2. A preliminary two hour water run
of the centrifuge
3. A four hour wet run of the
centrifuge together with the polymer system, sludge feed system,
washwater system, and associated instrumentation and controls. Water
shall be used in this test for both the polymer and sludge feed
lines.
4. A final field test consisting of
a four hour sludge run. Polymer and sludge feed will be employed
and dewatered the sludge produced. Sludge feed system and polymer
feed system shall be part of this test.
3.7 FIELD PROCESS PERFORMANCE
TESTING
A. After satisfactory completion of
acceptance tests conducted on the centrifuge, each centrifuge shall
be performance tested for four (4), six-hour periods conducted over
a 5- day period to determine acceptable performance in accordance
with the Design Requirements. The OCSD reserves the right to select
and adjust test flow points (within the range given in Article 1.3
of this Specification. Performance tests shall be conducted two
times, once during the winter season and once during the summer
season (total of 8 tests runs over 2 performance tests) at dates
established by the OCSD. Each test run shall comply with the
performance requirements in Article of this Specification.
B. During each day’s performance
test, the CONTRACTOR shall be responsible for collecting all
required samples and measurements at 1/2 hour intervals in order to
make the following determinations. The first set of samples and
measurements shall be taken
1 hour after the beginning of the test
run.
1. Sludge feed – total solids.
2. Centrate – total solids.
3. Centrate – suspended solids.
4. Dewatered sludge – total
solids.
5. Polymer feed rate – gallons per
minute.
6. Sludge feed rate – gallons per
minute.
7. Centrifuge discharge rate –
pounds per hour.
8. Solids capture – percent.
9. Setting for polymer feed pump.
10. Setting for sludge feed pump.
11. Differential speed, torque
setting.
12. Motor amperage.
13. Power draw
C. During the entire Performance Test
period, all samples will be split, with one sample provided to OCSD
and the second sample delivered to a certified laboratory for
analysis. Laboratory tests will be performed by a certified lab
agreed upon by the CONTRACTOR, and ENGINEER, to obtain sludge feed
total percent solids, centrate total percent solids and suspended
solids, and dewatered total percent solids. The results will be
binding. The cost for independent laboratory analysis to be paid by
the Manufacturer.
D. All data collected during
performance tests shall be made available for the ENGINEER
for determining compliance with the Specifications. The ENGINEER
may request certified test data or call for on-site test to confirm
the accuracy of all instruments used in testing. All costs for
testing shall be borne by the Manufacturer.
E. Test records shall be maintained
to insure that the specified flow rates and polymer usage are met
throughout the duration of the test. The Manufacturer is
responsible for all necessary tools, meters, and test instruments.
F. Polymer dosage shall be
determined as the total active polymer consumed divided by the dry
solids fed to the machine during the test run period.
G. In the event the equipment is not
meeting the guaranteed performance, the manufacturer shall, at his
own expense, adjust or modify the equipment to meet these guaranteed
performance standards. All costs associated with the centrifuge
modifications shall be borne by the Manufacturer. The equipment
shall be modified and the test repeated until successfully
completed. New test results will govern.
H. Manufacturer shall have the
use of two polymer injection points during the performance
test: 1) Centrifuge feed tube and 2) centrifuge feed piping.
Polymer injection points will be the same as the existing units.
3.8 TECHNICAL SERVICES
Technical Services of the
manufacturer’s representative shall be supplied in the following
areas:
A. Field Service Technician
Qualifications
1. The Manufacturer shall dispatch
factory-trained technicians to service the equipment. The
technicians shall be in the direct employ of the Manufacturer.
2. All field service shall be
supported by a fully qualified field service department. The field
service department shall be fully staffed with at least 20 full time
employees, all of whom are factory-trained for the equipment.
3. Field service department shall be
within a driving distance from OCSD.
4. Field service department shall
have spare parts readily available.
5. Field service shall be available
24 hours per day, 7 days per week. B. Start-Up Services:
1. Furnish the services of
authorized technical representatives of the Manufacturer to
assist/inspect the equipment, conduct pre-operational mechanical
checkout of the equipment, place equipment into operation, optimize
the performances of the equipment and perform the field performance
testing. These services shall be per Schedule 11365-2.
2. See Specification section 01820,
Training of OCSD Personnel, for additional training requirements.
|
Schedule 11365-2
Dewatering Centrifuge Start-Up Services |
|||
|
|
Minimum Requirements |
||
|
|
|
Number of Personnel |
|
|
Installation Inspection
Inspect Piping, Chutes, Flex.
Connections Installation
Inspect Wiring and Control
Installation PLC Programming and Trouble-Shooting Mechanical
Start-up (Checkout)
Process Start-up (Checkout)
Field Performance Testing |
6
2
8
15
10
10
15 |
1
1
1
1
2
2
2 |
6
2
8
15
20
20
30 |
|
Total |
|
|
101 |
C. Emergency Service:
1. Provide the services of the
Manufacturer to be present within 24 hours for on-site emergency
services of all the furnished equipment. Emergency service shall
be required for failure of any major component of the centrifuge
equipment.
2. Emergency service shall be
provided at no charge throughout the 1 year warranty period
from the day of OCSD acceptance.
D. Training:
1. The manufacturer shall provide
operation and maintenance training as follows:
a. Operations Training: three (3)
days, 8 hours per day not including travel time of classroom and
hands-on instruction which will cover the theory of operation,
actual operation of the centrifuge, polymer systems, and
optimization of the centrifuge operations. Operations training
shall cover OCSD’s personnel on weekends and on the daily three
(3) shifts.
b. Maintenance Training: Three (3)
days of classroom and hands-on training, either during or after the
operations training, in separate sessions for Electrical
maintenance, Instrumentation maintenance, and mechanical
maintenance. Each class shall be a minimum of 4 hours per day and
conducted between the hours of
8 am to 4 pm.
2. The equipment manufacturer shall
schedule no less than 3 days (8 hours per day not including travel
time) to supervise maintenance of the equipment over the 1 year
period following acceptance.
3. Additional training is defined in
Division 17.
3.9 FIRST YEAR OPERATIONS
AND MAINTENANCE ASSISTANCE SERVICES AGREEMENT (O&MASA)
A. In addition to commissioning,
training and other on-site services described elsewhere in this
Specification section, the Centrifuge manufacturer shall provide a
listing of all operations and maintenance required on the
centrifuges. OCSD shall select the services to be provided by the
Centrifuge manufacturer for a period of eight months following RAT
acceptance.
B. The O&MASA is intended to
cover the assistance of a factory certified service technician to
operate, service and maintain centrifuges in accordance with the
factory established operation and maintenance procedures.
C. The technician’s role shall be
assisting in but not limited to the following items:
1. Assistance with regular operation
and maintenance as specified in the operation and maintenance
manual for the centrifuge, which includes performance
optimization, inspections, adjustments and routine maintenance of
each centrifuge.
2. Assistance with preventative
maintenance based on the actual cumulative running hours of
operation of the equipment and includes scheduled inspections as
well as maintenance of wear components.
3. Assistance with Bi-Annual (twice
yearly) inspections including check and adjust the equipment in
accordance with the requirements of the Lubrication and Maintenance
Schedule.
3.10 OCSD ACCEPTANCE
B. The OCSD will accept only
complete, workable equipment and systems under the following
conditions:
1. After receipt by OCSD of all the
Work Drawings in “Accepted” or “Accepted as
Noted ” status by the ENGINEER.
2. After receipt by OCSD of all
centrifuge documentation required by the Contract.
3. After completion of all specified
factory testing and receipt of all factory test reports accepted by
the ENGINEER.
4. After completion of all specified
equipment cleaning, start-up, field testing and accepted performance
runs as specified herein and receipt by OCSD of all specification
certifications accepted by the ENGINEER.
5. After receipt by OCSD of all spare
parts and complete final draft of service manuals as specified
herein.
6. After completion of Operator
Training Schedule as specified herein.
No comments:
Post a Comment