Air-main charging systems

Protecting compressed air quality – no overwhelming of the air treatment system

Compressed air treatment systems are designed for a certain rate of air flow which, when the system is operating at full load, pushes against the pressurised air in the air distribution network. However, should this resistance not be present, for example during periods of low load or downtime, it is possible that dryers and filters may be "overwhelmed" by the sudden surge in airflow that occurs when the system re-starts. DHS air-main charging systems reliably prevent this from occurring.

Thanks to a patented pulse width modulating control concept, every DHS air-main charging system is ready-prepared for all eventualities and, as is Kaeser‘s way, combines exceptional operational reliability with straightforward operation.

  • Connection diameters from G ½ to G 3 and DN 40 to DN 400
  • For systems with one or more treatment lines
  • Perfect integration thanks to various interfaces, configuration options and retrofit kits

Your advantages

  • Protection from impermissible air flow:
    With dropping pressure, the speed of flow in the pipework will quickly increase and potentially cause an overload of all air system components. The installation of a Kaeser DHS air-main charging system guarantees the required minimum pressure and ensures reliable operation, and in particular when re-starting the system following a shut-down.
  • Gentle pressure build-up in the system:
    A pulse width modulated control designed by Kaeser ensures that system intervention opening and closing sequences are performed in very small steps.
  • A brilliantly simple operating concept:
    Easy configuration in 25 languages, immediate recognition of the operating state, manual emergency-stop – time-saving features that also increase safety.

Your investment advantage: KAESER Life-Cycle Management
Life-cycle costs

Even the best components are only as good as their integration into the overall system. With Kaeser, you benefit from individual consultation and intelligent technology that can be used universally and expanded as required.


Product details


Two operating modes

  • 1 – “Priority compressed air quality”, Pulse-width modulated opening and closing of ball valve and butterfly valve for efficient and proper operation of the compressed air supply.
  • 2 – "Priority compressed air quality" for redundant compressed air networks: in the event of dryer or filter faults, for example, closes off the affected line (set ex works)

Electronic control unit

  • Integrated electronic pressure sensor
  • Pressure regulator 0 – 16 bar
  • High-visibility LED
  • Mechanical indicator
  • Processor unit
  • Pressure monitoring
  • Display (25 languages)
  • Password protection
  • Operating mode selection switch
  • Control unit can be rotated 90°
  • Endpoint monitoring
  • Software update via microSD card
  • Anti-tamper seals for keyboard and operating mode switch to protect against unauthorised access
  • Multi voltage: 100 – 240 V AC, 50/60 Hz or 24 V DC

Pivot drive

  • Spring-loaded pneumatic pivot drive
  • Activates the ball or butterfly valve with internal control pressure
  • Silicone-free grease (standard) for ball and butterfly valve. Silicone-free is an option.


  • Password and operating parameter input via keyboard, e.g. opening pressure, hysteresis, opening/closing times in percent
  • Can be integrated into a master control system
  • Manual operation using key to open in the event of power failure


  • Floating inputs for "external shut-down" e.g. dryer fault
  • Floating outputs for "group alarm", "open", "close" and "pressure monitoring"
  • 4-20 mA air distribution network signal for compressor controllers or master control systems
  • Connection for remote operation
  • Modbus-TCP communications interface with M12 plug-in connection.

Ball valve or butterfly valve

Endpoint mounting capability simplifies remodelling or expansion of the compressed air distribution network. It also facilitates alignment and securing in the pipeline for easy installation.


The DHS 4.0 is equipped as standard with a SIGMA NETWORK interface to make operation even more convenient.

We keep an eye on your compressed air station.
DHS 4.0 fitted to a compressed air station.

In order to ensure proper planning and to benefit from efficient and dependable compressed air system operation, the following should be taken into consideration: in addition to demand pressure and process air requirements, factors such as piping, cooling, ventilation, spatial conditions and environmental aspects should be included in the planning process. A well thought-out system design lays the foundation for effective operation later on. 

Generation, treatment and compressed air storage are essential components when it comes to the supply of compressed air. If the treatment components are overwhelmed by excessively high air flow rates, or if a treatment line is not effectively closed off in the event of a fault, unwanted contamination of the process air will occur. Moreover, unnecessary costs are incurred if the compressors also run at weekends in order to compensate for leakage losses.
With an air-main charging system from KAESER, these issues are a thing of the past.

Reliable compressed air supply with air main charging

Protect your components!

DHS air main charging system applications: Reliable compressed air supply with air main charging
  1. Compressor
  2. Refrigeration dryer with ECO-DRAIN
  3. Filtration with ECO-DRAIN
  4. Air receivers
  1. Electronic DHS 4.0 air-main charging system
  2. Aquamat condensate treatment
  3. Compressed air network

Since the network is often depressurised following periods of downtime, there is no flow resistance from the network pressure when the compressors are started. The compressed air treatment components in a compressed air supply system, however, are designed to accommodate the flow rates and speeds that occur in the distribution network when the system is in load operation. Therefore, without back-pressure present, there is the risk that filter and dryer components may become ‘overwhelmed’ by the sudden surge in airflow that occurs when the system re-starts. This can lead to filter element damage and to a raised pressure dew point in the refrigeration dryer. As a result, contaminants such as oil, particulate matter and humidity are introduced into the pipe distribution network and the process air.

Reliable compressed air quality with air-main charging

Trouble-free production!

Reliable compressed air quality with air-main charging
  1. Compressors
  2. Air receivers
  3. Refrigeration dryer with ECO-DRAIN
  4. Filtration with ECO-DRAIN
  1. Electronic DHS 4.0 air-main charging system
  3. Aquamat condensate treatment
  4. Compressed air network

Electronic air-main charging systems also prove highly useful during system operation - and are even essential for stations with multiple treatment lines - because they help assure consistently high compressed air quality. If a fault occurs with a dryer or a filter, for example, the air-main charging system is able to shut down and isolate the affected treatment line. This not only assures consistent air quality, but also safeguards the pipe distribution network and the air consumers in your production facility.

Technical specifications

The technical specifications can be found in this brochure: