Atlas Copco Inlet Valve Overhaul Ki Replacement – 2906049800

Atlas Copco 2906049800 – Inlet Valve Overhaul Kit

The Atlas Copco 2906049800 (2906-0498-00) is an Inlet Valve Overhaul Kit designed for servicing and restoring the inlet-valve assembly used in compatible Atlas Copco oil-free compressors.

The inlet valve controls the quantity of atmospheric air entering the compressor element. Correct inlet-valve operation is essential for compressor loading, unloading, capacity regulation and efficient operation.

Atlas Copco’s official catalog lists the kit weight as 800 g and provides a detailed list of the included components.

Working Process:

During compressor operation, atmospheric air enters through the compressor inlet system.

When compressed-air demand is present, the compressor control system positions the inlet valve toward the open position. This allows the required quantity of atmospheric air to enter the compressor element.

The compressor element compresses the incoming air and delivers the compressed air through the downstream system.

When the required operating pressure is reached or the controller requests reduced capacity, the inlet-valve mechanism changes position.

The inlet valve restricts the incoming airflow. This reduces the quantity of air entering the compressor element and therefore reduces compressor output.

When system pressure falls because of downstream air consumption, the control system commands the inlet valve toward the open position again.

The valve then permits increased airflow into the compressor element and the compressor resumes the required level of air production.

This automatic regulation of inlet airflow enables the compressor to respond to changing compressed-air demand.

Main Functions:

• Controls atmospheric air entering the compressor.
• Regulates compressor capacity.
• Supports loading and unloading.
• Maintains correct inlet-valve movement.
• Helps maintain stable compressor pressure.
• Reduces unnecessary airflow during reduced-load operation.
• Restores worn mechanical components during valve overhaul.
• Restores sealing and bearing performance.
• Helps prevent unwanted inlet/control-air leakage.

Official Kit Components:

Atlas Copco lists the following components for 2906049800:

• Bearing – 2 pcs
• O-ring – 1 pc
• Hexagon Nut M20 × 1.5 – 2 pcs
• Washer – 2 pcs
• Parallel Pin – 2 pcs
• Spring – 1 pc
• External Retaining Ring 20 mm – 1 pc
• Z 110–145 Inlet Valve Bearing Block – 1 pc
• Inlet Valve Kit – 1 pc
• Plain Bearing – 2 pcs
• Gasket – 1 pc

The official Atlas Copco catalog specifies a total kit weight of approximately 800 g.

Component Functions:

The bearings and plain bearings support the moving inlet-valve mechanism and allow controlled movement with reduced friction.

The inlet-valve bearing block provides structural support and maintains correct alignment of the valve mechanism.

The spring provides the required mechanical force for valve movement and return action.

The parallel pins provide accurate mechanical positioning and connection of the valve components.

The M20 × 1.5 hexagon nuts and washers secure the mechanical components during operation.

The external retaining ring holds the relevant component securely in its required position.

The O-ring and gasket provide sealing between mating components and help prevent unwanted air leakage.

The inlet valve kit contains the principal service components required to restore the inlet-valve operating mechanism.

Operating Cycle:

1. Start-up: The inlet-valve mechanism is placed in its required starting position.
2. Loading: The inlet valve opens to allow atmospheric air into the compressor element.
3. Air Intake: The required quantity of air enters the compression system.
4. Compression: The compressor element compresses the incoming air.
5. Pressure Build-up: System pressure increases.
6. Unload/Capacity Command: The controller requests reduced compressor output.
7. Valve Restriction: The inlet valve moves toward the restricted position.
8. Reduced Air Intake: Less air enters the compressor element.
9. Pressure Reduction: Downstream air consumption lowers system pressure.
10. Reload Command: The controller requests increased capacity.
11. Valve Opening: The inlet valve moves toward its open operating position.
12. Normal Production: Increased airflow enters the compressor element and compressor output is restored.

This cycle repeats automatically according to compressed-air demand.

Importance of Bearings:

The inlet-valve mechanism contains moving components that require accurate alignment and smooth movement.

Worn bearings can create excessive mechanical clearance, friction or misalignment.

This can cause the valve to move slowly, stick or fail to reach the required operating position.

Replacing worn bearings during an overhaul helps restore smooth valve movement.

Role of the Spring:

The spring provides mechanical force for the inlet-valve mechanism.

A weakened, damaged or incorrectly installed spring can affect valve movement and prevent the inlet valve from reaching the correct position.

This may result in incomplete loading, unloading or capacity regulation.

Role of the O-Ring and Gasket:

The O-ring and gasket provide sealing between relevant valve components.

During long-term operation, sealing materials may harden, flatten, crack or lose elasticity.

A damaged seal can result in air leakage and reduced control performance.

Replacing these sealing components during overhaul helps restore the required sealing characteristics.

Possible Failure Conditions:

Long-term compressor operation can cause mechanical wear, contamination, seal deterioration and spring fatigue.

Potential problems include:

• Worn bearings
• Worn plain bearings
• Damaged spring
• Damaged O-ring
• Damaged gasket
• Loose or worn mechanical connections
• Worn retaining components
• Valve misalignment
• Valve sticking
• Restricted valve movement
• Inlet-air leakage

Typical compressor symptoms may include:

• Compressor fails to load correctly.
• Compressor fails to unload correctly.
• Reduced air delivery.
• Slow pressure build-up.
• Unstable operating pressure.
• Incorrect compressor capacity.
• Excessive energy consumption.
• Delayed valve response.
• Abnormal load/unload cycling.
• Air leakage around the inlet-valve assembly.

If the inlet valve remains too restricted during loading, insufficient air enters the compressor element and compressor output may decrease.

If the valve remains too open during unloading, the compressor may process unnecessary air and consume additional energy.

Maintenance / Overhaul Procedure:

Before servicing the inlet valve, stop the compressor, isolate the electrical supply and completely depressurize the compressor according to the applicable Atlas Copco safety procedure.

Inspect the complete inlet-valve assembly for:

• Bearing wear
• Plain-bearing wear
• Spring condition
• O-ring deterioration
• Gasket condition
• Pin and retaining-ring condition
• Mechanical clearance
• Valve alignment
• Contamination
• Air leakage

Remove the worn components carefully without damaging the valve housing or mating surfaces.

Clean the components and sealing surfaces before assembly.

Install the components supplied with the 2906049800 Inlet Valve Overhaul Kit according to the applicable Atlas Copco service instructions.

Ensure that:

• Bearings are correctly positioned.
• Plain bearings are correctly installed.
• The spring is installed in the correct orientation.
• Pins are properly fitted.
• Washers and nuts are correctly secured.
• The retaining ring is properly seated.
• O-ring and gasket are correctly positioned.
• The inlet-valve bearing block is correctly aligned.

Check the valve mechanism for smooth and unrestricted movement before returning the compressor to service.

After assembly, restart the compressor and monitor several operating cycles.

Verify:

• Correct loading.
• Correct unloading.
• Normal pressure build-up.
• Normal compressed-air delivery.
• Stable operating pressure.
• Smooth inlet-valve movement.
• No abnormal air leakage.
• Correct response to control commands.

A properly overhauled inlet valve restores the mechanical movement, alignment, bearing support and sealing performance required for reliable compressor operation.

The Atlas Copco 2906049800 Inlet Valve Overhaul Kit therefore helps restore the inlet-valve assembly to proper operating condition and supports dependable compressor capacity control.

Part Number: 2906049800
Alternative Number: 2906-0498-00 / 2906 0498 00
Brand: Atlas Copco
Official Description: Inlet Valve Overhaul Kit for Oil-Free Compressors
Application: Atlas Copco oil-free compressors
Known Application: Z 110–145 inlet-valve configuration
Official Listed Weight: 800 g
Component Type: Inlet valve overhaul/service kit
Primary Function: Controls airflow entering the compressor element
Secondary Function: Supports compressor loading, unloading and capacity regulation
Main Components: Bearings, plain bearings, spring, O-ring, gasket, pins, washers, nuts, retaining ring, bearing block and inlet-valve kit
Operating Function: Regulates inlet airflow according to compressor operating demand
Main Benefits: Restored valve movement, improved sealing, reduced mechanical wear, reliable capacity regulation and dependable compressor operation.

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