Kiln Miscellaneous

Rotary Kiln Maintenance Seminar

Kiln Miscellaneous

Kiln Miscellaneous Kiln Inlet Seal Kiln Outlet Seal Thrust Roller Hydraulic Thrust Roller Kiln Maintenance Checklist The Good Old Days

Kiln Inlet Seal

Kiln Inlet Seal

The kiln seal prevents cold air from entering the process and driving up fuel costs. The seal must remain tight while accommodating kiln run-out and longitudinal movement.

Kiln Pneumatic Inlet Seal

Pneumatic Cylinders

The pneumatic seal consists of two sliding surfaces pushed together by pneumatic cylinders.

Kiln Inlet Seal Pneumatic Cylinders Seal Detail

Spring Loaded Graphite Plug

Kiln Inlet Seal Detail Sliding Contact Stationary Sealing Surface

Rotating Sealing Surface

Graphite Plugs Wire Rope Graphite Seal Cord

Stationary Kiln Inlet Hood

Rotating Kiln Shell

Kiln Inlet Seal Carriage

Turnbuckle

The seal is suspended by a carriage which allows it to move longitudinally as the kiln expands and contracts.

Pneumatic Inlet Seal

Stationary Seal Half

Rotating Seal Half

The pneumatic cylinders, when pressurized, will press the two seal halves tightly together.

Filter, Regulator, Lubricator

Cylinder force is controlled by adjusting the air pressure. A lubricator prevents cylinder corrosion and seize-up. The filter keeps condensation and dirt out of the cylinder.

Filter, Regulator, Lubricator

Kiln Inlet Seal

Spring Loaded Graphite Plug

Graphite Plugs in Seal Plate

The seal’s sliding surfaces are graphite lubricated.

Kiln Inlet Castings

Castings on the inlet hood and kiln inlet cone keep the castable refractory in place. Inspect them at annual shutdown.

Spring Plate Inlet Seal

Spring Plate Inlet Seal

Spring Plate Inlet Seal

Spring Plate Inlet Seal

No, covering the spring plates with plastic won’t help.

Outlet Seal

Kiln Outlet Seal

The spring plate outlet seal has become the outlet seal of choice. The seal can withstand the harsh conditions at the kiln hood.

Kiln Outlet Seal

Spring Plate

Wire Rope

Kiln Outlet Seal

Counterweight

Spring plates are wrapped with a counterweighted wire rope arrangement to keep them tight against the cowl.

Kiln Outlet Seal

Forced Air Cooling

A stainless steel cowl at the kiln outlet provides an air channel for cooling of the kiln discharge castings and the spring plate contact surface.

Kiln Outlet Seal

Spring plates are bolted on and are easily replaced.

Kiln Outlet Seal

The Old Way

The Better Way

Dust from kiln hood puffing falls down the chutes to the drag chain conveyor or into the clinker cooler.

Kiln Outlet Sector

The kiln nose rings sees severe service and must be regularly inspected for refractory and casting failure.

Kiln Outlet Seal

This alternate spring plates design features outwardly protruding spring plates.

Kiln Outlet Seal

Outwardly protruding spring plate design.

The Most Expensive Seal

A bad seal allows cold air into the kiln. The cost of extra fuel to heat this cold air can amount to tens of thousands of dollars per year.

Thrust Roller

Thrust Roller Assembly Clearance Oil Seal Oil Level Pipe

Tire Tie Rod

Spherical Bearings

Shims

Keep the clearance to a minimum (6mm), and adjust the shims to keep the kiln gear in proper longitudinal alignment.

Thrust Roller Assembly

Set Screws

The kiln position can be controlled by adjusting set screws on this thrust roller base.

Thrust Roller Position Stop Ring

Thrust Tire

The thrust roller is positioned to maintain proper hot running alignment between kiln gear and pinion. Repositioning may be necessary as stop rings wear.

Thrust Roller Misalignment

Roller Tilted to Left

Roller Offset to Left

Roller Tilted to Right

Roller Offset to Right

A misaligned thrust roller will result in vertical forces on the roller as shown above.

Thrust Roller Misalignment

An improperly aligned thrust roller can ride out of its socket, causing damage to tire stop blocks.

Thrust Roller

Thrust rollers can become overloaded if the kiln’s supporting rollers are improperly skewed. This thrust roller base became deformed from excessive force.

Fuller Thrust Roller

Fuller Thrust Roller

Hydraulic Thrust Roller

Hydraulic Thrust Roller

The hydraulic thrust roller maintains a constant, controlled force on the thrust tire and keeps the kiln in an electronically determined position.

Hydraulic Thrust Roller Position Sensor

Hydraulic Cylinder

Guide Bar

Hydraulic Thrust Roller Breather

Oil Level Sight Glass

Guide Bar Grease Fittings

The spherical bearings are lubricated with ISO VG 1000 gear oil. Guide bars are grease lubricated.

Thrust Roller

The roller surface is graphite lubricated.

Hydraulic Thrust Roller

Hydraulic Cabinet

The hydraulic power unit is normally placed beneath the kiln’s thrust pier.

Hydraulic Cabinet

Relief Valve

Tank

Accumulator Directional Valve Pump

Hydraulic Pump

The axial piston pump has manual adjustments for pressure and flow rate.

Directional Valve

A directional valve directs fluid to the thrust cylinder, or allows the cylinder to bleed down.

Hydro-pneumatic Accumulator

An accumulator stores hydraulic energy. It is used to maintain a steady force on the thrust tire even though the tire wobbles slightly as the kiln turns.

Hydro-pneumatic Accumulator Gas Valve

Nitrogen Gas

Bladder

Anti-Extrusion Valve

Shell

Port

The accumulator contains a rubber bladder which is charged with nitrogen gas.

Hydro-pneumatic Accumulator

1000 500

1500

0

2000

psig

System Pressure Less Than pprecharge

1000

1000

500

1500

500

1500

0

2000

0

2000

psig

System Pressure at pmax

psig

System Pressure at pmin

When hydraulic pressure increases and decreases the gas is compressed and expanded.

Hydro-pneumatic Accumulator

Danger! Do not charge with air or oxygen!

The accumulator is pre-charged with nitrogen to approximately half of the expected average operating hydraulic pressure.

Pressure Relief Valve

A pressure relief valve limits hydraulic pressure in the system. This prevents excessive downhill kiln force from damaging the thrust roller.

Hydraulic Filter

An in-tank filter with a 10 micron element keeps hydraulic fluid clean. The protruding red button indicates the element needs changing.

Thrust Cylinder LVDT

An LVDT (linear variable differential transformer) mounted in the hydraulic cylinder measures the distance that the cylinder rod is extended.

Thrust System LVDT Cabinet

The LVDT signal goes to a cabinet where the kiln’s hot running axial position is set and where alarms are programmed for excessive uphill and downhill kiln position.

Fuller Hydraulic Thrust Roller

Fuller Hydraulic Thrust Roller

Preventive Maintenance Checklist

Daily Thrust Roller •

Kilns with one thrust roller (mech. or hyd.) – visual check of the thrust rollers including recording of the thrust pressure (ideal 500 psi, can vary from 200-800 psi). Maximum design pressure is 12001300 psi – check the temperature of the thrust roller housing and face.

•

Kilns with two thrust rollers – Observe the kiln position relative to the uphill or downhill thrust rollers – Check temperature of the housing and thrust roller face if there is constant contact.

Daily Seals •

Visually check feed and discharge seals

Gear •

Visually check the gear and pinion

Rollers and Live Rings •

Visually check all roller and tire surfaces

•

Lubricate contact faces between tires and shell mounted tire pads and stop blocks using a mixture of graphite powder and water.

Daily Temperatures •

Record kiln shell temperatures and include a night visual inspection for “hot spots”

Weekly • • • • • •

Check and record direction of thrust on all rollers. Check lubrication on all support rollers. Check oil levels in support roller bearings and thrust roller bearings. Check and record the tire creep and clearance. Record related shell and tire temperatures. Check condition of tire stop blocks and wear rings.

Weekly •

Check general condition of kiln shell.

•

Check contact patterns between gear and pinion by observing the oil smear on the contact face for at least one full kiln rotation.

Annually •

Perform complete check of kiln alignment utilizing the laser or mechanical alignment method. Kiln alignments should be completed after major repairs have been made to the kiln.

•

With this information recorded and compared, a problem should be caught before a real dilemma occurs (i.e. an unplanned shutdown).

•

Prior to planned kiln shutdowns, an extensive mechanical inspection should be completed to determine repairs required.

The Good Old Days

The Good Old Days

The Good Old Days

Rivets

Don’t Be Mean to Your Kiln