SCR-XA scroll compressors

SCR-XA scroll compressor in a closed sound-insulated enclosure with touch panel

Class 0 · TÜV Rheinland

A scroll compressor compresses air between two scrolls that never touch and therefore need no lubricant. No oil ends up at the outlet — not even as the mist a filter would have to clean up. The SCR-XA range offers seven power classes from 2.2 to 29.6 kW, each in three pressures, and is certified to Class 0 under ISO 8573-1 by the notified body TÜV Rheinland.

2.2–29.6 kWtotal power input

200–3,520 l/minfree air delivery

55–74 dB(A)noise level

Class 0oil content to ISO 8573-1

Choosing a model: three questions

The range has 21 combinations, but only three things decide. Answer them in this order and you will be left with one or two machines.

How much air will you use?

Add up the consumption of tools and machines that can run at the same time, and add a reserve. The range covers a band from 200 l/min (one surgery, a small laboratory) to 3,520 l/min (a production line). Free air delivery is measured to ISO 1217, Annex C, so it is comparable with other manufacturers’ figures.

What pressure do you actually need?

This is the question where the most money is saved. The same machine delivers markedly less air at 10 bar than at 7 — on the SCR-2XA it is 200 instead of 250 l/min, a fifth less for the same power input. Buying the ten-bar version "just in case" means paying for air you will not get.

Will the machine run flat out, or in bursts?

From the SCR-7XA up, the machines are built from several independent scroll blocks (2, 3, 4, 6 or 8 of them). The SCR9000 unit brings them in one by one as demand rises, so at half the consumption half the blocks run. A fluctuating demand is therefore a reason to go multi-block even when one large machine would cover the peak.

SCR-XA technical data

SCR-XA scroll compressors — all 21 versions
Order code	Power	Pressure	Free air delivery (l/min)	Outlet	Dimensions L × W × H (mm)	Weight	Noise level
SCR-2/7XA	2,2 kW	7 bar	250	1/2"	550 × 470 × 770	110 kg	55 dB(A)
SCR-2/8XA		8 bar	240
SCR-2/10XA		10 bar	200
SCR-4/7XA	3,7 kW	7 bar	420	3/4"	1 100 × 650 × 980	230 kg	60 dB(A)
SCR-4/8XA		8 bar	400
SCR-4/10XA		10 bar	350
SCR-7/7XA	7,4 kW	7 bar	840	1"	1 200 × 650 × 998	280 kg	60 dB(A)
SCR-7/8XA		8 bar	800
SCR-7/10XA		10 bar	700
SCR-11/7XA	11,1 kW	7 bar	1 230	1"	1 300 × 800 × 1 403	450 kg	65 dB(A)
SCR-11/8XA		8 bar	1 200
SCR-11/10XA		10 bar	1 000
SCR-15/7XA	14,8 kW	7 bar	1 640	1"	1 300 × 800 × 1 808	650 kg	70 dB(A)
SCR-15/8XA		8 bar	1 600
SCR-15/10XA		10 bar	1 400
SCR-22/7XA	22,2 kW	7 bar	2 620	1"	1 400 × 1 300 × 1 410	900 kg	72 dB(A)
SCR-22/8XA		8 bar	2 600
SCR-22/10XA		10 bar	2 100
SCR-30/7XA	29,6 kW	7 bar	3 520	1"	1 400 × 1 300 × 1 808	1 300 kg	74 dB(A)
SCR-30/8XA		8 bar	3 500
SCR-30/10XA		10 bar	2 800

Free air delivery is measured to ISO 1217, Annex C. The noise level is sound pressure to ISO 2151. The air purity class is defined by ISO 8573-1. The figures given are the manufacturer’s rated data and apply to intake air at 20 °C and 1 bar absolute.

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What sets the XA range apart

Class 0, not "almost oil-free"

ISO 8573-1 defines classes 0 to 6. Class 1 permits 0.01 mg of oil per m³; Class 0 is stricter and has to be proven by measurement. On the SCR-XA it was verified by TÜV Rheinland.

ANEST IWATA blocks

The scroll blocks come from ANEST IWATA of Japan, the world’s largest maker of these units. All of them are produced on a robotic line, so the dimensional tolerances of the scrolls stay consistent.

Multi-block design

From the SCR-7XA up, the machine is assembled from 3.7 kW blocks. A failure of one block does not mean a stopped plant — the others keep running and the machine works at reduced output.

SCR9000 control

Colour seven-inch touchscreen, energy consumption metering, four pressure bands, weekly run scheduling, Modbus RS485 and network control of up to sixteen compressors.

Maintenance with no oil circuit

There is nothing to replace — no oil, no separator, no disposal of oil-contaminated condensate. Servicing comes down to filters, belts and inspection.

How the SCR-XA scroll compressor works

How the scroll compresses air

Four stages of air compression between the fixed and the orbiting scroll

The block consists of two interleaved scrolls: one fixed, the other performing an orbiting motion. Air is drawn in at the outer circumference, sealed into pockets between the scrolls, and carried towards the centre. On the way the pocket volume shrinks steadily and the pressure rises. Compression is therefore continuous — with none of the pulsation that shakes the pipework on piston machines.

Inside the scroll block

Exploded view of an ANEST IWATA scroll block — cooler, fixed scroll, orbiting scroll, bearing housing and fan

The exploded view shows the whole unit: cooler, fixed scroll, orbiting scroll, bearing housing with shaft, and fan. The scrolls never touch in operation and the gap between them is sealed by the shape itself. That is why there is no oil here and no sealing rings to wear away.

How the machine is put together

SCR-XA layout: the frame with blocks and one block with motor and V-belts, labelled with eight numbers

Intake filter, scroll block, V-belts, electric motor, air cooler, fans, safety valve and pressure and temperature sensors — on multi-block machines this whole assembly is repeated as many times as the machine has blocks, and the blocks sit in a common frame.

Multi-block design from 7.4 kW

SCR-30XA with panels removed — eight scroll blocks on three levels

The SCR-30XA in the picture has eight blocks on three levels. The SCR9000 unit does not switch them on together: it brings them in one at a time as demand requires, while watching the running hours so that they wear evenly. That is also why the range needs no variable speed drive — output is not regulated by speed but by the number of running blocks.

Control and electrical installation

Open electrical cabinet of the SCR-XA scroll compressor with breakers and terminal block

Behind the front panel sits the electrical cabinet with breakers, contactors and a terminal block; above it the SCR9000 control unit. It is operated from a touchscreen or eight buttons, handles four pressure bands, a weekly run schedule, automatic restart after a power cut and energy consumption metering. Via Modbus RS485 it can join a network control of up to sixteen compressors.

Cooling and heat removal

Two compressed air coolers and the electric motor inside a multi-block SCR-XA

Every block has its own compressed air cooler and its own fan. The heat leaves through the rear, where the fans are stacked one above the other — allow for that when siting the machine and leave clear space behind it.

Where oil-free air is used

Oil in the air is a problem anywhere the air touches the product, the packaging or a person. In these plants an oil-free machine is not bought for comfort, but because nothing else will do.

Dental surgery — oil-free compressed air for a dental chair unit — Dentistry and hospitals — The air goes straight into the patient’s mouth

Shelves of medicines — pharmaceutical production requires Class 0 air — Pharmaceuticals — Drug manufacturing tolerates no trace of hydrocarbons

Laboratory bench with analytical instruments supplied with compressed air — Laboratories — Analytical instruments need constant purity

Populating printed circuit boards — semiconductor production free of oil mist — Semiconductor manufacturing — Oil mist ruins an entire batch of wafers

Beverage filling line — compressed air in direct contact with the packaging — Beverage industry — The air touches both the drink and the packaging

Spray gun painting a car body — air with no oil — Paint shops — A drop of oil in a painted surface is a crater

Blow moulding plastic bottles — compressed air for food packaging — Plastics processing — Blow moulding PET packaging for food

Food packing line — conveyors driven by oil-free air — Food industry — Packing lines and conveyors in direct contact

When a scroll compressor is not the answer

The XA range is built for purity and quiet, not for maximum output per pound. If a trace of oil in the air does not bother you, the same money buys considerably more air from a screw compressor.

SCR screw compressors — More output per kilowatt, but the air carries oil mist
Oil-free piston compressors — Cheaper and smaller machines for intermittent duty, but louder and with pulsation
Compressed air dryers — Class 0 deals with oil, not moisture — that still has to be dried out

Ventilek advises

The commonest mistake I hear: "I will take the ten-bar version so I have a reserve." Except that the same machine gives you a fifth less air at 10 bar than at 7 — and the power input stays the same. Look at the SCR-2XA in the table: 250 l/min at seven bar, 200 l/min at ten. Buy the pressure you actually need, not pressure for peace of mind.

Frequently asked questions

How does a scroll compressor work?: Air is sealed between two interleaved scrolls — one stationary, the other orbiting. The pockets of air travel from the outer edge towards the centre and shrink on the way, which raises the pressure. The scrolls never touch, so there is nothing to lubricate. A fuller comparison with the other principles is in our article on compressor principles.
How does it differ from an oil-free piston compressor?: An oil-free piston machine has a dry ring on the piston which wears and is a consumable. The scroll touches nothing, so it lasts considerably longer and runs more quietly and without pulsation. We go through the differences in the article scroll versus diaphragm compressor.
Does Class 0 also mean dry air?: No. Class 0 under ISO 8573-1 concerns oil content. Moisture is a separate quantity and is dealt with by a dryer. An oil-free compressor without a dryer delivers clean but moist air.
Does the XA range need a variable speed drive?: It does not. On multi-block machines the output is regulated by the number of running scroll blocks, not by speed. The SCR9000 unit sequences the blocks and loads them evenly.
How loud is such a machine?: From 55 dB(A) on the SCR-2XA to 74 dB(A) on the SCR-30XA. The smallest models can go in the next room with no building work; from 15 kW up a separate compressor room becomes worthwhile.
Can the compressor be rented?: Yes. The SCRent programme offers a five-year rental in monthly instalments that also cover servicing, pressure vessel inspections and emergency call-outs.

Scroll compressor SCR-30/10XA total power input 29.6 kW, working pressure 10 bar, free air delivery 168 Nm³/h

Code: SCR-30/10XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-30/8XA total power input 29.6 kW, working pressure 8 bar, free air delivery 210 Nm³/h

Code: SCR-30/8XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-30/7XA total power input 29.6 kW, working pressure 7 bar, free air delivery 211.2 Nm³/h

Code: SCR-30/7XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-22/8XA total power input 22.2 kW, working pressure 8 bar, free air delivery 156 Nm³/h

Code: SCR-22/8XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-22/7XA total power input 22.2 kW, working pressure 7 bar, free air delivery 157.2 Nm³/h

Code: SCR-22/7XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-22/10XA total power input 22.2 kW, working pressure 10 bar, free air delivery 126 Nm³/h

Code: SCR-22/10XA

€0,05

(€0,04 excl. VAT)

Scroll compressor SCR-15/10XA total power input 14.8 kW, working pressure 10 bar, free air delivery 84 Nm³/h

Code: SCR-15/10XA

€21 660,12

(€17 900,93 excl. VAT)

Scroll compressor SCR-15/8XA total power input 14.8 kW, working pressure 8 bar, free air delivery 96 Nm³/h

Code: SCR-15/8XA

€21 660,12

(€17 900,93 excl. VAT)

Scroll compressor SCR-15/7XA total power input 14.8 kW, working pressure 7 bar, free air delivery 98.4 Nm³/h

Code: SCR-15/7XA

€21 660,12

(€17 900,93 excl. VAT)

Scroll compressor SCR-11/10XA total power input 11.1 kW, working pressure 10 bar, free air delivery 60 Nm³/h

Code: SCR-11/10XA

€18 396,27

(€15 203,53 excl. VAT)

21 items total

SCR-XA scroll compressors

Choosing a model: three questions

How much air will you use?

What pressure do you actually need?

Will the machine run flat out, or in bursts?

SCR-XA technical data

What sets the XA range apart

Class 0, not "almost oil-free"

ANEST IWATA blocks

Multi-block design

SCR9000 control

Maintenance with no oil circuit

How the SCR-XA scroll compressor works

How the scroll compresses air

Inside the scroll block

How the machine is put together

Multi-block design from 7.4 kW

Control and electrical installation

Cooling and heat removal

Where oil-free air is used

When a scroll compressor is not the answer

Ventilek advises

Frequently asked questions

Bestsellers

Product sorting

List of products

Listing controls

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