AirCom DBM User manual

DBM
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Operating Instructions
1. Intended use
Pressure limiting valves for compressed air, gases or fluids for reducing briefly occurring
pressure surges or to prevent an impermissible high pressure increase in the system.
Pressure limiting valves cannot be used as flow rate regulating elements or stop valves.
The pressure limiting valves of the series DBM are a type of compact spring-loaded pressure limiter.
The general function of a pressure limiter is described in the following film. Animation film pressure limiter
2. Information on the usage instructions
Any handling of the device is under the condition that these usage instructions are understood and followed. The
device is intended only for the application described.
2.1 Symbols
This symbol points out special information or mandatory or prohibited actions to prevent damage.
 These instructions serve the purpose of occupational safety!
 This symbol is placed next to important instructions, for observing regulations or if there is a
 risk of material damage.
3. Safety
3.1 Safety information
 Do not endanger yourself or others. Read the following safety information before you
 install, operate or repair fixtures.
 They serve to avoid danger to persons and the plant. The handling of technical gases – in
particular flammable, self-igniting or toxic gases – requires expertise, the observation of these usage instructions
and special safety measures. Additionally, any relevant regulations and guidelines must be observed. (see 3.2)
Use the fixtures only as intended (see section "Intended use"). The same is valid for the medium used with them:
Improper usage can damage the system or even lead to injuries which could be fatal.
Employ gas monitoring devices if you are handling dangerous gases. These monitoring products detect leaks and
warn personnel.
Wear respirator mask, safety goggles as well as safety gloves if you work with toxic gases and ensure good
ventilation. Make sure that exhaust openings cannot be plugged up and that toxic gases can be exhausted on
fixtures and plants accordingly with venting valves. Some gases can displace oxygen from the air and cause
suffocation. Make sure you have good ventilation when using such gases. It is quite recommendable to install
detectors that emit an alarm in case of a lack of oxygen at the workplace.
DBM Pressure limiting valve
Oils and greases must never be used on gas regulating systems. They can ignite easily and react violently with
some pressurised gases. In special cases, lubricants can be used that are suited then for the respective
application. Implementing AirCom pressure limiting valves in oxygen applications is only permitted with
appropriately marked devices.
Special safety information for pressure limiting valves.
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DBM
If devices are connected to the pressure limiting valve, the setting of the pressure limiting valve needs to ensure that
no dangerous pressure can build up. The medium discharging from the outlet of the pressure limiting valve has to be
carried away in a defined manner.
When changing the type of gas, the pressure limiting valve should be purged sufficiently with inert gas.
3.2 Regulations and guidelines
The following regulations and guidelines must be observed in Germany on a case-by-case
 basis:
   - Standards of prevention
  - Operating working materials
  - Guidelines for laboratories
  - Ordinance on Industrial Safety and Health
  - Data sheet "Dangerous substances"
4. Installation
4.1 Transport and packaging
When the pressure limiting valves are delivered, please check for possible transport damage or defects. The
connection openings of the pressure limiting valves may be closed for transport by caps to prevent dirt particles from
entering. Do not remove the caps until just before installation. In case of a later disassembly, the connection
openings need to be closed again before being put into storage or being transported. This can also be done
provisionally by a strip of adhesive tape that is taped over the opening.
The transport of the pressure limiting valve (e.g. sending to customer service) may be done only in a suitable sturdy
package.
4.2 Preparation
• Turn the adjusting screw (hand wheel, spindle, hexagon) on the pressure limiting valve anticlockwise until the
range spring is completely relaxed.
• Connect pressure limiting valve – connection threads have to match.
• To ensure the pressure limiting valve is in perfect working condition, all lines needs to be purged prior to
installation. Deposits and other foreign objects can cause damage to the valve seat, and thus interfere with the
regulating function or make it impossible. No lubricants may be used during installation. The pressure limiting valve
may soil and there is a risk of burning out if oxygen or nitrous oxide is used.
DBM Pressure limiting valve
The pressure limiting valve has to be installed in the line in such a way that the medium flows in the direction of the
arrows stamped/adhered onto the housing (IN to OUT). Internal filters are only for the protection against possible
soiling during the installation. It is recommended to use external input pressure filters. All gaseous media should be
free of moisture to prevent icing of the pressure limiting valve at high flow rates.
4.3 Operating
The desired upstream pressure is set by turning the adjusting screw (hand wheel, spindle, hexagon). Turning
clockwise increases the upstream pressure, turning anticlockwise reduces the upstream pressure.
The general function of a pressure limiting valve is described in the following film.
Animation film pressure limiter
Fine adjustments should always be made in the direction of upstream pressure increase in order to reach the
precise setting point. These pressure limiting valves function with all media that are compatible with the specified
materials.
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The pressure limiting valves may only be operated within the values specified in the technical specifications. An
operation outside of the permitted values can overload and damage the seals.
Warning:
With some devices, "overtightening" the adjusting screw (hand wheel, spindle, hexagon) can lead to a much higher
upstream pressure than the maximum factory-specified value.
Operating a pressure limiting valve with a much higher pressure than the factory-specified upstream pressure can
have the following consequences:
• If the setting spring is compressed to a value near the block length, it will show a greatly changed characteristic
curve with a negative effect on the regulating function of the pressure limiting valve (e.g. incomplete opening of the
regulating valve, indicated by a creeping delayed rise or fall of the upstream pressure).
• The internal parts will be subjected to loads beyond their design limits which might deform them permanently.
Damages due to an excessively high setting of the upstream pressure are excluded from any warranty.
4.4 Shutting down
• Close inlet.
• Consume remaining medium completely or drain completely.
• Turn the hand wheel anticlockwise until the pressure range spring is completely relaxed.
5. Maintenance
Do not carry out any maintenance/repair on fixtures that are under
 pressure!

Repair and maintenance may only be carried out by trained technicians! Under normal operating conditions, an
inspection is recommended every 6 months during which the device is inspected for external damage and the
function is checked. If operating conditions are unusually excessive, shorter maintenance intervals may be
necessary.
5.1 Troubleshooting
1. Problem: After adjusting the pressure limiting valve, the upstream pressure continues to rise even without any
turns to the adjusting screw (hand wheel, spindle, hexagon).
Possible cause: The valve seat is soiled or the diaphragm or the piston is damaged. Measure: The valve seat,
diaphragm or the piston needs to be cleaned or replaced.
2. Leakages around or at the spring cap or permanent discharging at the output.
Possible cause:
1. The spring cap needs to be retightened.
2. 2.There is dirt or there are scratches on the valve tappet / diaphragm / piston.
Measure: Replace the diaphragm / piston or the tappet (repair kit)
5.3 Spare parts
Only original spare parts may be used for repairs. Replacements are to be carried out only by trained personnel. You
can find spare parts at www.aircom.net
5.4 Repairs
Defective devices can be sent in to AirCom Pneumatic GmbH. After a thorough inspection, a cost estimate is
created with results of the inspection.
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Pressure limiting valves that are not used with compressed air or neutral gases need to be cleaned or
purged with inert gas before they are sent in. Additionally the medium used as well as a fault description
needs to be listed in the cover letter.
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