ROBERTSON AIR SYSTEMS
TWIN CYCLONE BUS VACUUM SYSTEM
||Work Included: This
section describes the requirements for labor, materials, equipment, and services necessary to furnish,
fabricate, and install a modular dual cyclone bus vacuum
system. Site preparation including footings, compressed
air, power, and water are not a part of this work.
||Electrical Work: Electrical
work shall be in accordance with the applicable
provisions of the National Electric Code.
Verification: Contractor shall verify field
clearances, dimensions, and actual conditions of the
area. Any discrepancy that may affect proper installation
work shall be promptly reported to the project engineers.
It shall be the responsibility of the contractor to
undertake corrective measures, as directed by the project
engineers, before starting the work as specified.
the installation of the bus vacuum systems with site
preparation of the fuel island.
Regulations: The bus vacuum system shall be in
accordance with national and commercial standards, codes,
rules and regulations, local ordinances, and other
authorities having jurisdiction on this work.
Qualifications: The manufacturer shall have been
regularly engaged in design and manufacture of specified
modular equipment in satisfactory commercial
use/operation for a period of at least five years.
||Shop Drawings: Submit
shop drawings with complete installation and erection
details along with assembly and detail drawings for
review by engineer.
Literature: Technical literature on the assembly
and components shall be submitted for review by Engineer.
Maintenance Manuals: All instruction and
maintenance manuals shall be submitted for review by
Systems: The bus interior vacuum cleaner system
shall be the same as manufactured by Robertson Air
Systems or equal. It shall be designed and constructed
for sustained heavy-duty utilization of daily bus fleet
cleaning. During the vacuuming procedure, the industrial
blowers shall cause air movement within the bus of
sufficient velocity to capture and transport dust and
debris into the cleaner. Dust and debris shall be
transported through the buses' front door into the
bellows, then upward through a connecting flex duct and
into the double cyclone centrifugal dust separator unit.
Dust and debris shall pass through the bottom discharge
cones into the sealed trash container with clean air
exhausting out the top of the cyclone separators.
Operation: A bus is then driven into place for
vacuuming and fueling and parked with it's wheels
approximately 6" from the curb and it's rear door or
window are opened. The bellows mounted "START"
push button is then pressed and shall move the bellows
forward, turn on the atomizing misters, and open the
stack dampers. The bellows shall seal against the
periphery of the door opening. Cleaning personnel shall
take the air gun and move to the rear of the bus and with
the hand-held air gun, sweep from under seats stirring up
dust and debris. Deodorant shall be dispersed through the
bus while the air gun is being used. Pushing of the
"STOP" button on the bellows shall
automatically move the bellows away from the bus to a
retracted position, rewind the hose reel, time stop the
blowers, turn off the atomizing misters and close the two
stack dampers. The blowers shall run for approximately 5
minutes and then stop
system equipment and accessory specifications contained
herein are to be considered as minimum and typical only
of the type required to provide a workable system. Any
manufacturer or distributor providing equipment which
meets or exceeds specifications and performance shall be
equally considered in bid evaluation, provided it shall
be contained within the specified space.
Cleaning: The interior vacuum cleaning of buses
shall be a function accomplished during daily fleet
fueling and servicing. Buses shall be driven through the
service lanes, with simultaneous fare-box retrieval and
data download, fueling, servicing, and interior cleaning
occurring at each servicing station. Bus time on-station
during all service and cleaning functions averages four
to seven minutes. Installed vacuum cleaner assemblies
shall be capable of effective bus interior vacuum
cleaning within two to three minutes.
Vacuum cleaner operation shall not exceed 87 DBA 5 feet
above floor level and 5 feet in front of cyclones with
the stack dampers open. The noise level shall not exceed
83 DBA with the dampers shut.
62 AMPS per system
460 VAC, 60 Hz, 3-phase
115 VAC, 60 Hz, single-phase
||Central compressed air:
||100 psig and 34 cfm per
vac system shall be installed as directed either
preceding and/or following the service island and shall
be connected to the cyclone/blower assembly with flex
||Floor Space: Total
floor space occupied by the complete assembly shall be no
greater than 14 feet 6 inches long by 5 feet 9 inches
wide. The height shall be a maximum of 19 feet above the
service island. Equipment shall not impede passage of
||Dust Control Atomizing Spray
Nozzles (optional) located on the inlet to the
cyclone. The nozzles will emit microscopic water
particles that will attach to the dust particles 10-50
microns in size and cause them to drop out during
separation and collection.
Description for Each Vacuum System: Items
necessary for a complete and working installation with
major assemblies or components are as follows:
||Air blow guns (one at each
station, with 16 inch sweeper barrel).
||Bellows assembly--28 inch
minimum travel. In retracted position, the bellow shall
leave 11 inches horizontal. clearance to the top of the
curb, so that passage between the bellows and bus doors
||Supporting steel frame
with four legs of 4 inch by 3/8 inch angle.
||Separator assembly to
include two 48 inch centrifugal dust cyclone separators;
electric motor; industrial exhaust fan; discharge cone;
and spring-loaded, hinged, gasketed lid for container.
||The blowers include two
in-line BCS blowers that pull clean air off the top of
||Atomized misters dampen
the air entering the cyclones with microscopic water
particles. The water particles attach to the dust
particles (10 to 50 microns in size) and cause them to
drop out during separation. Each atomizing nozzles shall
emit approximately 1/2 gallon of water every 2 hours.
||Electric components to
include electric motor starting equipment; overload
protection in all three phases controls and panels;
solenoid valves; selector switches; signal lights;
timers; and terminal strips; and circuit breakers and
overload reset buttons; and shall be in accordance with
consisting of one stainless steel vessel, in-line with
the air connection to the hose reel.
||Hose reel, located at the
bellows and/or at the rear door.
||Container--3 cubic yards
minimum, two required per position. The container shall
be on rubber wheels and compatible with the local
scavenger company's trucks.
||Pneumatic components to
include air controls and panels, isolating valves, air
cylinders, speed controls, air solenoid valves, air
filters, air pressure regulator, and pressure gauges.
anchor bolts, and fasteners.
||Retractable bellows: The bellows shall extend
toward the bus sealing against the side of the bus
outside the doors with neoprene rubber on all contacting
surfaces. The vertical seals shall be flexible to permit
them to conform to straight or curved surfaces. Allowable
leakage shall be a maximum of 8 percent. In the retracted
position, neither bearings nor rails shall obstruct the
area on top of the curb in front of the bus door. The
forward and backward movement shall be imparted by a
pneumatic piston located beneath the cover plate. The
bellows shall consist of the following components
starting at the bottom.
||A 1/4 inch cover plate
with wheels and piston.
||A vertical bulkhead
supporting the air exhaust opening, pushbuttons, two
louvers and top seal.
||Two double skinned louvers
with spring-loaded neoprene rubber seals along the
vertical leading edges shall form the seal along the
outside of the bus outside the doors. The forward flap
and rear flap shall have a two-position pneumatic control
for either "narrow" or "wide" doors.
||A spring loaded top seal
covering the top of the vertical frame with neoprene
rubber along the leading edge shall seal across the top
of the doors.
||Blowers: The blowers shall
"pull" clean air off each cyclone top discharge
opening and be an industrial in-line BCS type, standard
construction, rated for 12,000 cfm at 7-1/2 in WG S.P.
using a 25-hp, 3-60-220/460, TEFC motor and including
fixed pitch V-belt drive; access door; and belt guard.
Each vacuum system shall be equipped with two blowers.
Assembly: The separator assembly shall consist
of two 48 inch diameter cyclones with 16 inch diameter
bottom discharge openings and 23 inch diameter stacks, 16
inch diameter by 10 inch long flexhaust connector; and a
hinged spring loaded lid. The cyclone shell shall be
minimum 12 gauge. The inlet shall have a gradual
transition from the blower discharge to an area that
shall limit the inlet velocity to 3500 feet minimum. Each
cyclone shall have a cylindrical self-cleaning wire mesh
screen on the inside below the stack to prevent
carry-over of light floatables, such as small pieces of
paper. The support structure shall be capable of
supporting the blower, motor, stack dampers, lid, and
cyclones. It shall have sufficient cross bracing to
prevent vibration of the entire structure.
trash container shall be 72 inches long by 50 inches wide
by 51-3/4 inches high with a 2 inch wide lip on top. The
sides shall be minimum 14 gauge and adequately supported
to prevent distortion with a 8 inch H20 positive
pressure. The ends shall have guides for lifting with a
front fork-lift type disposal truck. The trash container
shall be mounted on four vulcanized rubber-tired casters,
each rated for 1000 lbs. minimum. The four casters shall
be the swivel type. It shall have its own hinged sheet
metal cover to protect the collected material from being
blown out while being stored prior to collection by the
disposal truck. The trash container shall have two rigid
steel hand grips to facilitate movement. The trash
container box shall be of sufficient capacity to hold the
dust and debris for 250 buses before requiring emptying
or replacing. The trash container shall be removable by
releasing the hold-down clamps on the spring loaded lid
and wheeling it by hand to a temporary storage area where
it shall later be unloaded by a disposal truck. Two
cyclone assembly mounted guides shall help the trash
container line up with the lid after dumping.
||Hose Reel: The
hose reel shall be an American Reeling Device Model
1105-18-02 or equivalent. Air rewind, open heavy-duty
type, with a capacity of 60 feet of 3/8 inch hose, sealed
for life bearing, and rolled edge sheaves. Includes 60
feet of 3/8 inch I.D. 800 psig minimum burst pressure air
hose with 1/4 inch male pipe thread air line coupler.
Reels shall be integral with the packaged vacuum system
located behind the bellows with the hose passing through
the bellows. A timer, not a contact switch, shall be used
to stop the rewind cycle. A 12 inch nipple at the swivel
shall prevent the hose from wrapping around the swivel
The Robertson Air Systems air gun shall be 16 inches long
with a amflo booster nozzle attached the front tip. It
shall be rated for 34 cfm full flow at 100 psig line
System: The ASME stainless steel pressure vessel
shall be installed in- line to the air connection going
to the hose reel. The solid odor neutralizing mass shall
be placed inside the pressure vessel so as to slowly
evaporate as air passes through the vessel. The odor
neutralizing solid mass shall be Mother Nature's Odor Remover or equal.
||Electric Panel: Electric
panel shall be pre-wired 480V, 3 phase, 60 hz, NEMA 12,
electrical control panel and shall be installed at each
bellows containing a combination motor/starter. Provide
overload protection in all three phases and all other
necessary control relays, timers, and terminal blocks
shall be furnished. Fan "Start/Stop" push
buttons and pilot light shall be on the control panel
||Pneumatic Panel: The
panel shall have air controls for each vacuum line
mounted on the bellows unit in its own enclosure. An
air-control panel shall be mounted on the main support
frame and shall contain a main shutoff valve, blow-down
valve, Manual filter, and manifold leading to all
controls. Each cylinder or pair of cylinders shall be
controlled by its own air regulator. A gauge shall
indicate the regulated pressure. All air-solenoid valves
and pneumatic pressure switch shall be mounted on this
panel. The panel shall contain all necessary controls to
control one lane of vacuum operation.
metal parts not galvanized shall be cleaned and covered
with two coats of primer and two finish coats of
semi-gloss industrial enamel paint. The finish color is
to be selected by the district or project engineers.
||Lid: The lid shall be 54 1/2 inches
wide by 76 inches long using 2 inch by 2 inch by 1/4 inch
square pipe frame with a 14 gage cover. It shall have a 1
inch by 1 1/2 inch hollow rubber seal fastened to the
bottom with screws. It shall have two 15 3/4 inch
diameter by 2 inch high collars on top for connecting
flex duct to the cyclones. The lid shall be supported by
above from 1 garage door spring and 2-1 1/2"
springs. The lid shall lift approximately 1" up all
around the trash container when unclamped. The clamps
shall be a De-sta-co 53810 or equal and fasten the lid to
the trash container in 4 places.
Dampers: Two cyclone
discharge opening stack dampers shall be installed to
completely stop air from flowing through the vacuum
system while the bellows is retracted. The stack dampers
shall be a Model B476-2 or equivalent and shall consist
of a 1/2" circular plate with a rubber seal that
covers the blower discharge opening. The circular plate
shall hinge on a 1" shaft located on one side of the
discharge opening. The 1" shaft shall turn in two
pillow block bearings. The stack dampers shall be
actuated by a 3" by 10" air piston connected to
an actuating arm protruding from one side of the 1"
Level Detectors: Shall be acoustic type to
shut-off the blower in case of a plug in the cyclone. It
shall consist of an amplifier receiver (microphone) and a transmitter
(loudspeaker) with the two sensors located
18" above the bottom of the cones on opposite sides
of the cyclone. The sound shall not be audible to the
human ear and a timer shall prevent false alarms. It
shall shut-off the blower if a plug is detected.
Control (optional): Shall
consist of one to two air atomizing flat sprays to
produce a water particle size of 10 to 50 microns and
reduce emissions by 70%. Spray nozzles shall be directed
into the air stream to assist in capturing small
particles during the vacuuming cycle. Accessories located
in the pneumatic control cabinet shall consist of : a
liquid air regulator, an air regulator, two pressure
gages, a liquid filter, two 115v. solenoid valves, and
manual shut off valves.
||The bus vacuum systems
shall be installed in accordance with the manufacturer's
instructions under the direction of the manufacturer's
||Each component of the bus
vacuum system for each of the systems shall be tested for
||Each system shall be
tested for complete system operation. The following
readings shall be taken and tests made by a qualified
||Current on all three legs
of the fan motor with and without bus in position.
||CFM determined by pitot
tube traverse and manometer taken in the flexduct 2 feet
behind the bellows in the extended position with and
without a bus in position.
||Inlet air temperature.
||DB readings at 5 feet
above floor level, 5 feet in front of the bellows (in the
||After each of the systems
has been satisfactorily tested, all shall be tested with
a sufficient number of buses to be assured that the
installation shall clean buses in the specified time, as
in actual operation.
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