Atlas Copco +Z 4++ Check Valve Kit Replacement – 2906018700

Atlas Copco 2906018700 – +Z 4++ Check Valve Kit

The Atlas Copco 2906018700 (2906-0187-00) +Z 4++ Check Valve Kit is a service and replacement kit designed for compatible ZR/ZT oil-free compressor systems. Its primary function is to maintain one-way airflow through the compressor circuit and prevent reverse flow when operating pressure changes.

The kit is particularly associated with the +Z 4++ configuration and is used as a service kit for the check-valve mechanism. Atlas Copco’s official catalog lists the product as “+Z 4++ CHECK VLV KIT+ FOR ZR ZT OIL FREE COMPRESSORS.” The official listed weight is 136 g.

Working Process:

During normal compressor operation, compressed air flows through the designated discharge or air-treatment circuit in the intended direction. The check valve opens when the upstream pressure becomes sufficient to overcome the valve’s closing force.

Once the valve opens, compressed air can pass through the valve and continue toward the downstream side of the compressor system.

The check valve is designed to close when the pressure difference reverses. This prevents downstream pressure from flowing back toward the compressor.

Preventing reverse flow is particularly important in multi-stage oil-free compressor systems because reverse airflow can disturb pressure balance, cause unwanted rotation or loading conditions, and place unnecessary stress on compressor components.

The spring in the kit provides the closing force required to return the valve toward its closed position when the forward pressure differential disappears.

The rings, spring sleeves, lug bearings, and stoppins support the mechanical movement and positioning of the valve assembly. These components allow the valve mechanism to move correctly while maintaining the required alignment and closing action.

Atlas Copco’s official component list for 2906018700 specifies:

• Spring – 1 pc
• Ring – 2 pcs
• Spring Sleeve – 2 pcs
• Lug Bearing – 4 pcs
• Stoppin – 2 pcs

During normal operation, the check-valve components experience repeated opening and closing cycles, pressure fluctuations, vibration, and mechanical movement.

Over time, the spring can lose its original force, bearings can wear, sleeves can become damaged, and mechanical components can become contaminated or corroded.

A weakened or damaged spring may prevent the check valve from closing correctly. This can allow reverse airflow through the compressor circuit.

A worn bearing, sleeve, ring, or stoppin can cause excessive mechanical clearance or improper valve movement. This may result in leakage, unstable valve operation, abnormal noise, or reduced compressor efficiency.

If the valve becomes restricted or fails to open correctly, airflow through the system can be reduced. This can increase pressure losses and negatively affect compressor performance.

Maintenance Procedure:

Before servicing the check-valve assembly, the compressor must be stopped, electrically isolated, completely depressurized, and allowed to cool according to the applicable Atlas Copco safety procedure.

The existing check valve should be inspected for contamination, wear, corrosion, damaged mechanical components, abnormal clearances, and incorrect spring tension.

The 2906018700 Check Valve Kit should be used to replace the applicable worn components.

The spring, rings, spring sleeves, lug bearings, and stoppins must be installed in their correct positions and orientations according to the applicable Atlas Copco service documentation.

The valve mechanism should move freely without binding or excessive play.

After assembly, the compressor should be checked for air leakage and correct valve operation.

The compressor should then be started and monitored during loading, unloading, and shutdown.

During operation, the check valve should open when the required forward pressure differential is established and close when the pressure differential reverses.

Correct operation prevents unwanted reverse airflow and helps maintain the intended pressure direction through the compressor system.

The 2906018700 Check Valve Kit therefore helps restore reliable one-way airflow, correct valve movement, pressure stability, and dependable operation of compatible Atlas Copco oil-free compressor systems.

Part Number: 2906018700
Alternative Number: 2906-0187-00 / 2906 0187 00
Brand: Atlas Copco
Part Description: +Z 4++ Check Valve Kit
Official Description: +Z 4++ CHECK VLV KIT+ FOR ZR ZT OIL FREE COMPRESSORS
Component Type: Check valve service kit
Application: Compatible Atlas Copco ZR/ZT oil-free compressors
Official Listed Weight: 136 g
Main Components: Spring, rings, spring sleeves, lug bearings, and stoppins
Primary Function: Maintains one-way airflow
Secondary Function: Prevents reverse airflow when pressure conditions change
Operating Function: Opens under forward pressure differential and closes when flow attempts to reverse
Main Benefits: Reverse-flow protection, reliable pressure control, reduced leakage, stable valve operation, and dependable compressor performance.

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