The document summarizes Atlas Copco's DM oil-free high-pressure piston compressor. Key points: - The DM compressor utilizes Atlas Copco's oil-free high-pressure technology to compress gases up to 440 bar without oil contamination. It has a hermetically sealed compressor-motor unit to prevent gas losses. - The vertical, 2-5 stage compressor is designed for applications like natural gas refueling stations where space is limited. It is oil-free, air-cooled, and incorporates innovative scotch yoke technology. - The compressor reliably compresses gases like natural gas, hydrogen, nitrogen and air without oil carryover or need for oil disposal. It has high reliability and availability

1. OIL-FREE HIGH-PRESSURE
PISTON COMPRESSOR
DM (440 bar/37 kW)

2. OIL-FREE HIGH-PRESSURE
PISTON COMPRESSOR
DM (440 bar/37 kW)

3. PEAK PERFORMANCE
COMPRESSION
SYSTEMS
Atlas Copco manufactures high-end premium
products engineered by a world-class center of
excellence. Our commitment to quality is exemplified
by compliance with ISO 9001, ISO 14001 and OHAS
18001 certifications. We have a century of experience
in high-pressure technology and have installed
thousands of compressors worldwide for various
industrial gas and vehicle refueling applications. Our
DM high-pressure oil-free compressor range will
meet your needs for peak performance and optimal
efficiency.
HIGH-PRESSURE,
HIGH RELIABILITY,
AND NO OIL
CARRY-OVER
The DM compressor range utilizes Atlas Copco’s
revolutionary oil-free high-pressure technology.
It prevents oil from contaminating the gas. And it
eliminates concerns about oil disposal contaminating
the environment. The hermetically sealed compressor-motor
unit with magnetic coupling ensures no gas
losses to the atmosphere. The unique vertical design
of these 2-5 stage compressors is especially designed
for diverse gas compression applications where
space is at a premium.

4. DM HIGH-PRESSURE
OIL-FREE
COMPRESSORS
DM compressors are oil-free, air-cooled, high-pressure
piston machines incorporating inovative
scotch yoke technology in a vertical design.
Completely gas-tight, they are perfectly adapted to
applications such as natural gas vehicle refueling
stations, natural gas grid boosting, hydrogen
and other industrial gas compression for various
end uses.
Oil-free
With its unique scotch yoke design converting rotating
movements into linear movements, the DM compressor does
not require lube oil, hence will not contaminate the
compressed gas with oil carry-over. It also does not require
oil disposal processes, or power consumption for crankcase
heaters in cold weather.
Gas-tight
The hermetically sealed pressurized crankcase means that
the DM compressor is absolutely gas-tight. No gas will leak
to the atmosphere and no gas contamination from the
outside is possible. The suction process starts directly from
the pressurized crankcase with a range from atmospheric
pressure up to 39 bar(a) inlet pressure.
Easy maintenance
Thanks to the magnetic coupling, the compressor block can
be easily dismounted and replaced on site in less than a half
a day. The dismounted compressor block will then be
refurbished in the factory to guarantee the shortest
downtime and maximum availability.

5. COMPRESSED GAS WHEN YOU NEED IT
The DM compressor gives you high-pressure gas with high availability, outstanding cost-efficiency, and
low environmental impact. Whatever your process, natural gas, biomethane, nitrogen, hydrogen, air or
CO2 will be compressed up to 350 bar (450 bar for hydrogen) with no oil contamination, no gas losses
and the highest safety and availability.

6. Scotch yoke principle for balanced forces
The choice of a scotch yoke as reciprocating motion allows the conversion of the
rotational motion of the prime drive into a linear motion. The reciprocating parts are
directly coupled to a sliding yoke which allows a perfectly balanced centric drive in
an extremely compact format.
Scotch Yoke
degrees ATDC
Crank and slider degrees ATDC
1.5
1
0.5
0
-0.5
-1
-1.5
0.0004
0.0003
0.0002
0.0001
0
-0.0001
-0.0002
-0.0003
-0.0004
-0.0005
0
0
90
90
180
180
270
270
360
360
Displacement
Acceleration
Hermetically sealed pressurized crankcase compression
block in oil-free execution
The hermetically sealed oil-free compressor-motor unit with magnetic coupling ensures no gas losses
to the atmosphere and prevents gas contamination from the direct environment. This allows Zone
declassification from Zone 1 to Zone 2 in case of explosive gases.
The revolutionary oil-free high-pressure technology ensures no oil contamination of the gas, and
eliminates the risk of oil disposal contaminating the environment.
In addition to the economic and ecological advantages, the magnetic coupling allows a compression
unit to be changed in only a few hours, which leads to maximum compressor availability.

7. 1
2
4
5
6
SAFE FOR GAS APPLICATIONS
The DM compressors are safe for any gas application and fully comply with
ATEX and PED regulations.
1
2
3
4
Highly efficient: 2 to 5 compression stages
DM compressors are available with up to 5 compression stages to ensure low
compression ratios, reduced heat generation, and less wear.
5
Anti-vibration pads
DM compressors are assembled on a vertical frame,
isolated from their support by vibration dampening
elements. No special foundations are required.
Cooling air fan
Directly coupled to the main drive to ensure a constant air flow through the
whole unit.
Gas cooler
After each compression stage the gas is cooled by fins
around the gas pipes.
Magnetic coupling
The shaft is completely integrated in a hermetic housing with magnets ensuring
rotation. This eliminates risk of gas leakage, prevents wear, and eases
dismantling.

8. 7
3
8
9
10
11
12
6
Electric motor drive
• The drive is coupled at the bottom with a cooling air fan and at
the top with a magnetic coupling.
• Available for Zone 2, and optionally for Zone 1.
7
Hermetically sealed pressurized
crankcase
• Trunk piston technology enables the cylinders to fit on the
crankcase.
• Suction process starts directly from the pressurized crankcase
with up to 39 bar(a).
• No need for distance pieces, gaskets or stuffing boxes.
8
Pressure relief valves
A set of relief valves and gauges on inter-stage and discharge
side for optimized safety.
9
Separator after last compression stage
Interconnection gas pipes in stainless steel.
10
Relief valve collector
Each individual stage is collected back to suction.
11
Vertical frame
All elements are assembled on a steel base frame. The vertical
design allows an extremely small footprint of only 0.7 m2.
12
Cooling air channel
Ensures optimal cooling air flow through the complete
compressor.

9. OPTIMAL CONTROL OF YOUR
COMPRESSION SYSTEM
The SEKA II control unit is a fail-safe electronic board specifically developed to control compressors and
their system components. It allows fail-safe solutions to be set up quickly and with minimal maintenance
requirements. It eliminates the need for complex circuitry for monitoring systems (e.g. for suction pressure
or final output stage temperature). Interactive communication allows operators and service personnel to
identify and rectify problems quickly and effectively. This increases system availability and significantly
reduces maintenance and servicing costs.
SEKA II benefits
• Tested by the German Technical Inspection Agency (TÜV) for safety
circuits up to AK3.
• One-stop solution – including the main control component.
• Independency from PLC manufacturers and their products increases
your investment protection.
• Interactive communication helps faults to be rectified quickly.
• Remote monitoring allows service and operating personnel to
provide improved support.
• Straightforward monitoring (teleservice) also available for operators.
• Low maintenance and service costs.

10. CUSTOMER-FRIENDLY
DESIGN
Easy installation
With its extremely compact design and the smallest footprint in its
category, the DM compressor can be installed in any corner of your
premises. The compressor is mounted on anti-vibration pads. The
small footprint means that your system can easily be expanded in
the future with additional units without taking up significant extra
space.
Reduced maintenance
The DM compressor benefits from a unique and advanced
maintenance concept for very short downtimes. After being
dismounted from the compression unit at site, the compression
block will be replaced at site and the used one refurbished in our
factory. Exchanging the block takes less than half a day, after which
the new period of operation starts with a renewed compressor
block. This periodically executed process leads to smooth and
troublefree operation.

11. STANDARD SCOPE
AND FEATURES
Standard scope
2-5 stage oil-free compression block
Frame mounted in vertical arrangement
Hermetically sealed crankcase
Electric motor (Ex Zone 2 classification) with magnetic coupling
Working pressure up to 301 bar(a)
Stainless tubing and inter-stage air cooler
Set of gauges and safety valves on inter-stage and discharge side
Pressure transmitter at discharge side
Temperature transmitter at discharge side
Separator after final stage
Direct-driven cooling air fan
Anti-vibration pads
CE conformity
PED/ATEX conformity
Standard options
Cooling air channel for corner installation
Cooling air channel for free-standing installation
Electric cubicle with micro-electronic control
Engineered models
H2 execution
Zone 1 classification
60 Hz models
440 bar(g) execution
The DM compressor is ideal for CNG stations. We can provide a complete package with one or two compressors.

12. TECHNICAL
SPECIFICATIONS
Technical data
Suction pressure Up to 40 bar(a)
Working pressure Up to 451 bar(a)
Flow rate Up to 210 Nm3/h
Motor power 30 kW (37 kW)
Size 900 x 740 x 1700 mm (L x W x H)
Weight ca. 800 kg
Gases Natural gas, bio-methane, hydrogen, noble gases
Flow rate diagram
Volume Flow [Nm3/h] (0 °C; 1.013 bar(a))
Suction Pressure [bar(a)]
240
160
80
0
0 1 1.5 2.5 5.0 7.0 14.0 26.0 40.0

13. COMMITTED TO SUSTAINABLE PRODUCTIVITY
We stand by our responsibilities towards our customers, towards the environment and the
people around us. We make performance stand the test of time. This is what we call –
Sustainable Productivity.
www.atlascopco.com
2935 0602 10 – Printed in Belgium. Subject to alteration without prior notice. Never use compressed air as breathing air without prior purification in accordance with local legislation and standards.