Bronze Rotary Gear Pumps Introduction Installation, Operation, and Maintenance Instruction

Bronze Rotary Gear Pumps Introduction Installation, Operation, and Maintenance Instruction
Bronze Rotary Gear Pumps
Installation, Operation, and Maintenance Instruction
Introduction
Construction
Bronze Rotary Gear standard pump housings and helical gears are made of top quality bronze. Shafts are
stainless steel. Pumps are available with bronze bearings and grease fittings or with carbon bearings which
require no lubrication. Dynamic seal arrangements include packing, lip, or mechanical seals for a variety
of application requirements. Static cover o-ring seals eliminate gasket problems.
Application Range
Bronze Rotary Gear pumps are of the external gear positive displacement type, displacing a finite volume
of fluid with each shaft revolution. As such, capacity varies in direct proportion to pump speed. They are
suited to handle clear lubricating and non-lubricating fluids, with PH ranging from 4 to 11, and
temperatures to 400F. These pumps handle viscous fluids to 100,000 cps (462000 SSU) at reduced shaft
speeds, with flow rates to 175 GPM (662 LPM), differential pressures to 150 psig (10.3 BAR), and suction
lift capability to 20 feet (6.1 meters) for new pumps.
Field Inspection
Bronze Rotary Gear pumps may be readily inspected in the field usually without removal from the drive or
system plumbing. Simply remove the cover screws to pull the cover. Before attempting an inspection,
follow safety precautions and be sure to read and understand this manual.
New Pump Receipt Inspection
Upon receipt, check for obvious shipping damage and completeness to purchase order requirements.
Shortages or damage should be reported immediately to the carrier and to Cole-Parmer. Occasionally
during shipment, possible misalignment or other damage including cracked mechanical seal faces can
occur. As such, customers are advised to test the pump with water in a convenient location prior to
installing into the intended system.
Storage
If the pump is to be stored prior to installation, it is recommended that it be left in the original shipping
carton with all shipping plugs in place and stored in a dry environment avoiding temperature variations.
Contact the motor manufacturer for specific motor storage information.
Records
These instructions should be kept in a convenient location for ready reference. The manual should be read
carefully by persons responsible for installation, operation, and maintenance of the equipment. For ease of
reference, a copy of the order should be kept with the manual. Write down the pump model number as
shown on the pump nametag, and the date the unit was placed into service.
Installation
Site Preparation
Choose a site that allows easy access to the pump for maintenance. Consider protection from the elements.
Guard against drips and spray from nearby equipment. Choose a solid foundation for mounting. If noise is a
concern, consider a rubber pad under the pump base to dampen.
Flow Direction
Gear pumps will perform equally well in either direction however care must be taken for pumps equipped
with integral pressure relief valves. To change flow direction effectively reversing the suction and
discharge ports, simply switch driver rotation by following motor wiring diagram instructions and change
the location of the relief valve as shown below. Most pump motor units are factory supplied with
counterclockwise shaft rotation (when viewing the pump from the shaft end).
Suction Plumbing
Suction side plumbing considerations are key to desirable pump performance. Minimize head loss by
assuring sufficient pipe size (especially important for highly viscous services). Generally the same size pipe
as the pump ports is adequate. For long runs (beyond 3 feet) or viscous fluids, use one or two pipe sizes
larger. Strive to keep the lines as short and straight as possible. If flexible lines are used, they should be
selected to prevent wall collapse. To keep the pump from being starved or running dry, be sure there is
sufficient fluid supply. A flooded suction is generally preferred. Suction lifts over 3 vertical feet and long
horizontal runs (beyond 3 lineal feet) require a foot or check valve below the level of the liquid being
pumped. When taking suction from a tank or vessel, position the inlet above the maximum expected level
of solids. Use full-bore ball valves or gate valves to minimize restriction. Suction strainers should be
properly sized to minimize pressure drop and positioned for easy cleaning access. If start-up screens are
used, be sure they are removed prior to placing the system into regular operation. Orient lines so as to
prevent formation of air pockets. Be sure all joints are tight. Flush out all suction lines prior to installing the
pump.
General Piping
For further ease of maintenance, use union fittings to connect the pump to the system. Install a discharge
priming tee for convenience. Do not spring the piping to connect the pump. Use piping supports or hangers
as required. When necessary, provide for thermal expansion and contraction to avoid placing strain on the
pump.
Alignment
Proper alignment is key to seal and bearing performance. Improper alignment can lead to premature pump
failure. Check the alignment carefully between the pump and the drive.
Belt Drive
Though alignment is not as critical as direct connected, ensure that the pump and motor shafts are parallel
and in line. For units suitable for belt drive, be sure that the belt tension is adequate (per the belt
manufacturer’s recommendation) but do not overtighten. For heavy pulley loads, models are equipped with
external ball bearing supports. A single ½” (A or 4L section) V-belt is satisfactory for drive speeds up to 1
HP 3450 RPM. For larger drive sizes, double-V belts are recommended. Install guards around all moving
parts in accordance with OSHA to prevent personal injury.
Fasteners
Unless the pump has been shipped directly from the factory, it is recommended to check all bolts and nuts
for tightness to eliminate possible leakage problems or destructive vibration.
Pressure Relief
Discharge lines should be fitted with properly sized line pressure relief valves to protect both the pump and
the system. Pumps equipped with integral internal bypass relief valves are intended as a safety device
against intermittent overpressurization. They are not designed for continuous use and can lead to
overheating. In these instances, a line pressure relief valve is required. The relief outlet should be piped
back to the suction vessel.
Flow By-Pass
When a flow by-pass system is used to control output from the pump, the bypassed fluid should be directed
back to the suction vessel to avoid recirculation heat build-up. In cases where this is not possible, connect
to the suction at least 10 pipe diameters length away from the pump inlet. Provisions for cooling should be
made in the event of recirculation heat build-up.
Pump Driver Mounting
Adapter kits (including bracket, coupling components, and hardware) are available for Bronze Close
Coupled Gear pumps allowing connectivity to NEMA and IEC motor frames. Assembly instructions are
included with each kit. Adapterless motors, carbonator mounts, and electric clutches are available for some
models. Base mount kits (including baseplate, coupling components, coupling guard, and hardware) are
available for Bronze Pedestal Gear pumps. Contact your Cole-Parmer application specialist for additional
information.
Operation
Pre-Startup
Prior to start-up, recheck installation as described above. Follow National Electrical Code. Verify that
electrical service is properly grounded, fused, and adequately sized for motor nameplate requirements.
Check to be sure that motor wiring connections are correct referring to the wiring diagram on the motor
nameplate or inside the terminal box. Verify desired rotation by jogging the motor and make corrections if
necessary. Before initial startup, pre-wet the gears and make sure the pump is adequately primed. Failure to
do so could cause immediate damage to pump components. Make sure that discharge valves are open.
Startup
Start pump and check for proper operation. Adjust packing (if applicable) as necessary, allowing adequate
time to run in. Do not overtighten the packing else damage to the packing and the shaft can occur. A
properly packed and adjusted packing nut will leak at about 10 drops every 3 to 5 minutes. Tighten packing
nut only while shaft is rotating. Lip and mechanical seal versions require no adjustment. If the pump’s
bearing areas or seal area runs hot, shut the pump down and determine the cause. For units equipped with
integral pressure relief valve, the factory setting is usually 50 psig. It is recommended that the setting
should be 5 psig above the operating pressure in the discharge line. To increase the set point, turn the bypass valve adjusting screw clockwise. If start-up screens were used, be sure they are removed prior to
placing the system into regular operation. Depending on suction conditions, it may be necessary to reprime
the pump for subsequent restarts.
Warning
Dry running leads to immediate damage to pump components. Due to tight running clearances,
liquids containing solids and abrasives will accelerate pump wear. When possible, flush the pump
after each usage. Allowing liquid to freeze in the pump can cause damage.
Maintenance
Frequency
Since each installation differs, the frequency and extent of pump maintenance is best established based
upon past performance. Keeping detailed maintenance records of past performance aids in determining
future preventative maintenance intervals. During routine operating inspections, pay particular attention to
seal and bearing areas of the pump. Consult the motor manufacturer for motor maintenance instructions.
Caution
Before attempting to service the pump: Disconnect motor power and release all pressure within the
system. Flush the pump thoroughly with a neutralizing fluid before attempting to disassemble. Wear
appropriate personal protection equipment and handle the equipment with care.
Changing Applications
Verify that all wetted parts of the pump are compatible with the new fluid to be handled and that the motor
is adequately sized. Check with Cole-Parmer if in doubt.
Inspect for Wear
If your Bronze Gear Pump exhibits reduced flow, an inability to maintain pressure, is noisy or performs
otherwise abnormally, first refer to the Troubleshooting Matrix below. If the problem persists, the pump
should be inspected for wear or damage. Cole-Parmer Bronze Gear pump internals may be readily
inspected in the field usually without removal from the drive or system plumbing. Simply remove the cover
screws to pull the cover. Full pump removal and complete disassembly may be needed for a comprehensive
inspection. Refer to Cole-Parmer’s Bronze Gear Pump Inspection and Repair Manual for detailed
inspection and repair instructions covering a range of service life conditions including opened clearances,
bearing wear, gear wear, sheared pins, bulged covers, scoured shafts, and chemical deterioration.
Mechanical Seals
Pumps equipped with mechanical seals are of the standard pusher bellows type or wedge style. They can be
expected to provide long and troublefree service provided:
1)
2)
3)
4)
5)
Seal materials are compatible with pumped fluid and properly applied to the service.
Adequate cooling and lubrication is provided
Dry running is avoided
Abrasives are kept away from the seal area
Pump and driver are properly aligned
Detailed mechanical seal inspection and replacement instructions are included in Cole-Parmer’s Bronze
Gear Pump Inspection and Repair Manual.
Lip Seals
Pumps equipped with lip seals are of the metal cased, spring energized, single lip style. These are intended
to provide minimum friction drag with positive sealing and again should be maintenance free provided the
same conditions for mechanical seals are met as well as:
6) Avoid scouring of the shaft in the lip seal area due to contaminated abrasives
7) Avoid excessive seal lip contact pressure on the pump shaft due to excessive pump pressure.
These are readily replaceable by pressing out the old seal and pressing in a new replacement.
Packing
Pumps equipped with PTFE or graphoil packing require periodic adjustment as described above in the
Startup section to avoid excessive leakage. Eventually all the packing in the pump will become deteriorated
and will have to be replaced.
Recommended Spares
Repair kits are available for all Cole-Parmer Bronze Gear Pumps. For the proper kit, contact Cole-Parmer.
1)
2)
3)
4)
5)
6)
Troubleshooting Matrix
Probable Cause
Remedy
Closed valves
1) Open valves
Plugged suction
2) Eliminate restriction
Air leak at suction
3) Locate and repair leak
4) Do not exceed vapor pressure of liquid
Suction lift too high
5) Check wiring diagram
Motor wired incorrectly
6) Correct rotation
Wrong rotation
Low Liquid Delivery
1)
2)
3)
4)
5)
Pump shaft speed incorrect
Discharge pressure too high
Air leak at suction
Worn or damaged pump
Low viscosity
1)
2)
3)
4)
5)
Check driver speed, motor wiring, pulley tension
Reduce downstream pressure
Locate and repair leak
Inspect and repair as required
Verify original application conditions
Gradually Loses Prime
1)
2)
3)
4)
Suction lift too high
Air or gas in fluid
Air leak at suction
Worn or damaged pump
1)
2)
3)
4)
Improve suction pressure
Eliminate air or gas from fluid
Locate and repair leak
Inspect and repair as required
Noisy
1)
2)
3)
4)
Cavitating
Solid particles in fluid
Air or gas in fluid
Worn or damaged pump
1)
2)
3)
4)
Improve system suction pressure, provide adequate NPSH
Install suction strainer. Clean suction strainer.
Eliminate air or gas from fluid
Inspect and repair as required
Motor Runs Hot or Overloads
1) Discharge pressure too high
Difficulty
No Liquid Delivery
Seal Leaks
2) Shaft speed too fast
3) Fluid viscosity higher than
expected
4) Incorrectly wired motor
5) Binding internal pump parts
6) Motors normally feel hot
1) Dry running
2) Solids in fluid
3) Damaged during field
replacement
4) Seal material incompatible
with fluid
1) Reduce downstream pressure. Check relief valve setting.
Be sure discharge pressure gages functions correctly.
2) Reduce speed
3) Change to larger horsepower or higher service factor
motor. Thin fluid.
4) Check wiring diagram
5) Inspect and correct condition
6) Verify actual motor amperage draw is within rating.
1) Open valves. Prime pump.
2) Add suction strainer
3) Inspect and replace damaged components
4) Verify original application conditions. Consult factory
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