Atlas Copco Blowers and Boosters

A backing pump on its own slows down sharply as chamber pressure falls below a few Torr. An Atlas Copco ZRS booster pump sits on top of that backing pump and multiplies its pumping speed in the low-pressure range, so chambers reach working vacuum faster and hold it under higher gas loads. At Provac Sales, we supply Atlas Copco ZRS mechanical boosters new and rebuilt, size them to your existing backing pump, and offer repair and rebuild service for Atlas Copco vacuum equipment.

• Atlas Copco ZRS 250 booster, the smallest frame, suited to small coating, drying and packaging systems
• Atlas Copco ZRS 500 booster, about 335 CFM at 60 Hz, with an ISO100 inlet and ISO63 exhaust
• Atlas Copco ZRS 1200 booster, a mid-size water-cooled unit for larger chambers
• Atlas Copco ZRS 2600 booster, about 1,830 CFM at 60 Hz, with an ISO160 inlet and ISO100 exhaust
• Atlas Copco ZRS 4200 booster, the largest frame in the series, for big furnaces and space simulation chambers

Across the series, displacement runs from roughly 185/220 CFM to 2,440/2,935 CFM (50/60 Hz). Each product page lists the pumping speed, flange sizes, weight and recommended backing pumps. Condition, new or rebuilt, is confirmed on every quotation.

How a ZRS Booster Works

A ZRS booster is a Roots-type mechanical pump. Two figure-eight lobes rotate in opposite directions without touching each other or the housing, sweeping gas from the inlet to the outlet. Because there is no contact and no oil in the pumping chamber, the swept volume is oil-free. The gears and bearings are lubricated from separate oil reservoirs that are sealed off from the process gas.

A booster cannot exhaust to atmosphere. It must always be backed by a primary pump, such as an oil-sealed rotary vane, rotary piston or dry pump. The booster does the heavy lifting between roughly 50 mbar and 0.01 mbar, while the backing pump handles compression to atmosphere.

The Hydrokinetic Drive: No Bypass Valve Needed

Most Roots boosters need a pressure switch, a bypass line or a variable frequency drive to keep the motor from overloading when the booster starts at high pressure. Atlas Copco ZRS boosters use a patented hydrokinetic fluid drive instead. The fluid coupling lets the rotors slip and slow down automatically when the pressure difference is high, then speed up as pressure falls.

In practice, this means:

• The booster and backing pump can be started together at atmospheric pressure
• No pressure sensors, bypass lines or valves to install, wire or maintain
• Lower risk of motor overload or thermal trips during pump-down
• Simpler retrofits onto existing pumping lines

Maximum allowable pressure difference depends on the model, ranging from about 140/115 Torr on the smaller frames down to about 45/38 Torr on the largest. ZRS 1200 and larger units are water-cooled, so plan for a cooling water supply.

Matching a Booster to Your Backing Pump

Sizing a booster correctly matters more than picking the biggest one. As a rule of thumb, the booster's displacement should be roughly 4 to 10 times the backing pump's speed, depending on your target pressure and gas load. Atlas Copco publishes recommended pairings, for example:

• ZRS 500 with a GVD 80, GVD 175, GVS 100 or GVS 150 backing pump
• ZRS 2600 with a GVD 175 or GVD 275 backing pump
• ZRS boosters on GLS 250 or GLS 500 rotary piston pumps, which lifts system speed to roughly 294 to 1,530 CFM

Before ordering, confirm:

• Your backing pump model and pumping speed, including the 50 or 60 Hz rating
• Target operating pressure and typical gas load or leak rate
• Inlet and exhaust flange sizes on the existing pipework
• Supply voltage and phase
• Whether cooling water is available for water-cooled models
• Process gases, especially water vapor, solvents or powders

If you are building a new pumping system, browse our Atlas Copco vane pumps and Atlas Copco piston pumps collections for backing pumps that pair with ZRS boosters.

Applications for Atlas Copco Boosters

• Vacuum packaging and food processing
• Drying and degassing of oils, resins and components
• Vacuum metallurgy, heat treating and vacuum distillation
• Thin film coating and vacuum metallizing
• Freeze drying in pharmaceutical and food production
• Vacuum impregnation of electrical windings and castings
• Space simulation chambers and low-density wind tunnels

Signs Your Booster Needs Service

Booster problems often show up as slow pump-down rather than outright failure. Watch for:

• Longer pump-down times or a higher base pressure than usual
• New noise, knocking or vibration from the rotor housing
• Oil leaks at the shaft seals or oil appearing in the pumping chamber
• Dark, foamy or low oil in the gear or bearing reservoirs
• Overheating, or the motor tripping during start-up
• Rotors that feel tight or rub when turned by hand with power isolated

Check the backing pump first. A worn backing pump can make a healthy booster look weak. If the backing pump checks out, the booster likely needs bearings, seals or a full rebuild.

New vs Rebuilt ZRS Boosters

A new ZRS booster is the right choice for new systems, long warranty requirements or critical production lines. A rebuilt booster is often a cost-effective way to replace a failed unit on an existing system, especially for larger frames like the ZRS 2600 and 4200, where the price difference is significant. Rebuilt units are disassembled, cleaned, fitted with new bearings and seals as needed, and tested before shipping.

Atlas Copco Booster Repair and Rebuild

Provac Sales repairs and rebuilds Atlas Copco vacuum pumps, including ZRS boosters. Service can include teardown and inspection, bearing and seal replacement, rotor and housing evaluation, oil changes and a run test. Before shipping a unit, submit an RMA request, complete the contamination data sheet and drain the oil from the gear and bearing reservoirs. Learn more on our pump repair page.

Installation Tips

• Mount the booster level and support the pipework so no load sits on the flanges
• Fit an inlet screen if the process can release debris or flakes
• Fill the gear and bearing reservoirs to the sight glass with the correct oil before the first start
• Confirm rotation direction with a short bump test
• Connect cooling water on water-cooled models and check the flow before running
• Record pump-down time and base pressure on the first run as a benchmark for later

Find replacement booster oil in our vacuum fluids and greases collection.

Atlas Copco ZRS Boosters FAQ

1. Can an Atlas Copco ZRS booster run without a backing pump?

No. A ZRS booster cannot compress gas to atmosphere. It must always be paired with a backing pump, such as a GVD or GVS rotary vane pump, a GLS rotary piston pump or a suitable dry pump.

2. Do ZRS boosters need a bypass valve or pressure switch?

No. ZRS boosters use a hydrokinetic fluid drive that slows the rotors automatically at high pressure differences, so the booster and backing pump can start together without a bypass line, pressure switch or VFD.

3. Which backing pump should I use with a ZRS 500 booster?

Atlas Copco recommends backing the ZRS 500 with a GVD 80, GVD 175, GVS 100 or GVS 150. The right choice depends on your target pressure and gas load. Send us your process details and we will confirm the pairing.

4. Are Atlas Copco ZRS boosters water-cooled?

The ZRS 1200 and larger models are water-cooled. Smaller frames such as the ZRS 250 and ZRS 500 are air-cooled. Check the technical sheet for the exact model you are considering.

5. Can you rebuild my Atlas Copco booster?

Yes. Provac Sales repairs and rebuilds Atlas Copco vacuum equipment, including ZRS boosters. Submit an RMA, drain the oil and include the model, serial number and symptoms before shipping.

Request a Quote on Atlas Copco Boosters

Send us your backing pump model, target pressure, flange sizes and supply voltage. We will recommend the right ZRS booster, confirm new or rebuilt availability, or quote a repair of your existing unit. Contact us or call 831-462-8900.