Atlas Copco ZR 55 (FF) Oil-Free Rotary Screw Air Compressor

Description

The Atlas Copco ZR 55 is the 55 kW water-cooled machine of the ZR/ZT 55-90 oil-free family, a fixed-speed compressor that delivers certified oil-free air with the heat of compression carried out by the cooling water circuit. The compression chambers run completely free of oil, and the package carries the ISO 8573-1 CLASS 0 (2010) certification verified by TÜV.

Three pressure versions at 50 Hz and three at 60 Hz cover free air delivery from 123.1 to 160.2 l/s, and the Full Feature build integrates the IMD adsorption dryer inside the same package. The water-cooled design turns the compression heat into a resource instead of a loss.

Where the ZR 55 Sits in the Oil-Free Range

The ZR/ZT 55-90 family serves the plants whose oil-free demand fits a compact package instead of the larger ZR/ZT 110-275 class, and the ZR 55 carries 55 kW of installed motor power at the entry of the range. The letter Z marks the oil-free architecture: the precision-cut rotors never touch, so the compression chamber needs no lubrication and no oil can reach the air stream. Where the demand profile swings, the ZR 55 VSD of the same rating adjusts its speed continuously instead of loading and unloading.

Atlas Copco pioneered oil-free air technology over sixty years and became the first manufacturer awarded CLASS 0 certification. The ZR 55 brings that standard into the water-cooled 55 kW class, and the package arrives as a complete all-in-one installation: place it on a flat floor, connect the power line, the cooling water circuit and the air outlet, and push the start button.

Two Branches, One Platform

Two names describe the branches of the ZR 55, and each adds one fact:

• Standard — the compressor package delivers oil-free air for networks with external air treatment downstream, with the water-cooled design rejecting the heat of compression into the cooling water circuit.
• FF — Full Feature: the package integrates the IMD adsorption dryer, so dry air leaves the machine directly with no external energy spent on regeneration.

Every version combines with both branches, and both branches share the same 2,180 mm footprint. Plants that prefer air cooling instead of a water circuit pick the ZT 55 of the same rating.

Technical Specifications of the ZR 55

The table below condenses the ZR 55 into its headline figures:

Rated Data at 50 Hz

Unit performance is measured according to ISO 1217, annex C, edition 4 (2009). The 7.5 bar version is measured at 7 bar, the 8.6 bar version at 8 bar and the 10 bar version at 9 bar:

The 7.5 bar version leads the series at 148.3 l/s (314 cfm), and the 10 bar band delivers 123.1 l/s (261 cfm). The installed motor power stays at 55 kW across all versions, and the sound pressure level holds at 74 dB(A) at the work station.

Rated Data at 60 Hz

The 60 Hz versions cover three bands from 7.25 to 10.4 bar(e), and the motor is rated at 75 hp. The measurement pressures follow the same rule as at 50 Hz:

The 7.25 bar version tops the whole series at 160.2 l/s (340 cfm). The noise level is the A-weighted emission sound pressure level at the work station, measured according to ISO 2151: 2004 using ISO 9614/2, with a total uncertainty value of 3 dB(A).

Dimensions and Weight

The ZR 55 keeps one footprint across both branches, and the water-cooled design leaves the heat rejection to the cooling water circuit:

Both branches measure 2,180 mm in length, and no foundations are required for either one. The package installs directly on the flat floor of the compressor room, with the cooling water connections at the rear of the frame.

Class 0 Air Purity, Verified by TÜV

The ZR 55 belongs to the first compressor range in the industry certified oil-free according to ISO 8573-1 CLASS 0 (2010). TÜV type-tested the range with the most rigorous methodologies available, measuring all possible oil forms across a range of temperatures and pressures, and found no traces of oil at all in the output air stream. CLASS 0 is the most stringent class of the standard: the total oil concentration is as specified by the equipment user or supplier and more stringent than class 1.

That certification is what makes the ZR 55 the default choice where a single trace of oil costs a batch: food and beverage lines running fermentation, packaging and filling, electronics plants cleaning chips and boards, petrochemical operations in extreme heat and humidity, and pharmaceutical production from tablet coating to bottling.

Water Cooling and Heat Recovery

Water cooling defines the ZR branch of the family. The closed heat exchange path keeps the sound pressure level of the ZR 55 at 74 dB(A), two decibels below the air-cooled sibling, and holds the package stable in hot machine rooms because the cooling water carries the heat of compression out of the frame instead of the room air.

That recovered heat is an asset. The water-cooled design turns the compression heat into a source for process water, washing water or space heating, which raises the total energy efficiency of the site again instead of venting the energy into the machine room.

Full Feature: The Integrated IMD Adsorption Dryer

In the ZR 55 Full Feature, the IMD adsorption dryer eliminates the moisture before it enters the air net. The dryer uses the heat of the compressor for regeneration, so no external energy is needed to dry the air, and the savings against a conventional dryer are large. The pressure drop through the dryer is minimal, which cuts the operating cost again, and the whole drying function lives inside the compressor package instead of beside it.

Control and Monitoring

The Elektronikon unit controller runs the compressor and the integrated dryer from one control system. The high-resolution color display shows the running conditions with clear icons and intuitive navigation, monitors the maintenance status, and raises pro-active service indications, alarms for malfunctions and safety shutdowns. The display supports 31 different languages, and built-in remote control and notification functions come as standard with ethernet-based communication.

SMARTLINK and Options

The option list of the ZR 55 tailors the package to the plant:

• Monitoring and protection bundle — anti-condensation heaters, SPM bearing monitoring and PT 1000 sensors in the windings and bearings.
• SMARTLINK — online data monitoring of the compressed air system with warning indications and maintenance scheduling.
• PDP sensor and low load kit — Full Feature options for dew point verification and stable part-load running.
• Anchor pads, wooden case packaging, material certificates, test certificate and witnessed performance test — for controlled installation and documented acceptance.
• Teflon-free elements and purge kit for dry air during standstill — for specified coating materials and tropical environments.

Applications of the ZR 55

Food and beverage plants run the ZR 55 for fermentation, aeration, transportation, filling and capping, where the CLASS 0 certification removes the contamination risk from the audit trail. Electronics manufacturers use the clean, dry air for removing microscopic debris from chip and board surfaces, and petrochemical sites value the machine’s ability to run in extreme temperatures and humidity conditions around the clock.

Pharmaceutical production completes the picture, from fermentation and tablet coating to packing and bottling, where 100 percent oil-free air protects both the process and the brand. Where the demand profile fluctuates heavily, the plant adds the ZR 55 VSD of the same rating next to this fixed-speed machine, and growing networks step up to the ZR 75 of the same platform.

Service and Support Around the ZR 55

The ZR 55 is built for long overhaul intervals, few service interventions and minimal maintenance cost, and every machine is tested before delivery to ensure it meets the specifications. A global service operation with field service engineers across 160 countries backs the installed base, and genuine Atlas Copco parts keep the package at its rated performance.

Seadweer supplies genuine Atlas Copco spare parts and service kits for the ZR 55 and its Full Feature branch, and the parts coverage follows the same platform index as the ZR 55 VSD and the larger ZR 90. Send us the compressor model together with the parts you need, and the correct items are confirmed with the quotation in one pass.

FAQ

What does the ZR 55 deliver at 7.5 bar?

The 7.5 bar version delivers 148.3 l/s at 50 Hz, which equals 8.9 m³/min or 314 cfm, measured at 7 bar according to ISO 1217 annex C, edition 4 (2009). At 60 Hz the 7.25 bar version reads 160.2 l/s (340 cfm).

Is the ZR 55 water-cooled?

Yes. The ZR letter marks the water-cooled branch of the ZR/ZT family: the cooling water circuit carries the heat of compression out of the frame, which holds the sound level at 74 dB(A) and enables heat recovery. The air-cooled equivalent is the ZT 55.

How oil-free is the air?

The ZR 55 carries the ISO 8573-1 CLASS 0 (2010) certification verified by TÜV, the most stringent class of the standard. TÜV testing found no traces of oil at all in the output air stream across the tested range.

What does the Full Feature build add?

FF integrates the IMD adsorption dryer inside the compressor package. The dryer regenerates with the heat of the compressor, so no external energy is needed, and the package weight grows from 1,800 kg to 2,050 kg while the footprint stays at 2,180 × 1,450 × 2,184 mm.

How loud is the ZR 55?

The sound pressure level at the work station reads 74 dB(A) on every version at both frequencies. The value follows ISO 2151: 2004 with the ISO 9614/2 method and carries a total uncertainty value of 3 dB(A).

Does the ZR 55 need a cooling water main?

Yes, the water-cooled design expects a cooling water circuit on site, and that circuit is what enables the heat recovery to process water, washing water or space heating. Plants without a water main pick the air-cooled ZT 55 of the same rating.