Schmidt MV3, Руководство по эксплуатации и обслуживанию

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3.4 Blast System Air Supply Line
The air supply hose and fittings must be rated at a minimum of 150 psi operating pressure. The
air supply hose from the air compressor to the blast unit should be at least the same diameter as
the air inlet piping (see Section 9.0). This size hose will be large enough to supply the required
airflow to operate the blast unit controls and each blast nozzle. See Section 5.12 for further
information on air hose connection.
Note: If the abrasive blast system will be installed in a permanent location, the inlet connection
can be hard piped. Do Not install hard piping that is smaller than the piping size of the blast
system. Smaller piping size will reduce the air flow capacity. If other equipment will be using
the same source of air as the abrasive blaster, install a check valve at the air inlet. This will
protect against back flow of air pressure that can carry abrasive into the blast controls.
Hard piping connected to the abrasive blaster must be structurally supported so not to apply any
loading on the pressure vessel at the points of connection. Unsupported piping can create
bending loads at the pressure vessel connections which can cause damage and possible failure.
Hard piping connections to the pressure vessel must be designed and installed by qualified
personnel experienced with piping systems and the applicable codes pertaining to them.
External loading at piping connection can cause damage and possible failure of the pressure
vessel. Hard piping connected to the pressure vessel must include supports to eliminate the
possibility of applying loads on the pressure vessel.
3.5 Blast System Air Pressure
The maximum allowable working pressure (MAWP) for the blast unit is stamped on the ASME
nameplate attached to the vessel. For most abrasive blast systems the MAWP is 150psig. Do
Not exceed the MAWP. An air pressure regulator can be installed to reduce air supply pressure
that is higher than the MAWP. To prevent air pressure backflow only use a non-relieving air
regulator. Air pressure backflow will carry abrasive from the blast vessel and contaminate the
blast control system. Critical : Any inlet air valve or air pressure regulator added to the
system must have sufficient air flow capacity for proper operation of the blast system.
Insufficient air flow capacity will cause pressure drop in the blast system resulting in
equipment malfunction, abrasive backflow, and reduced blast productivity. Select a valve
that will operate with little or no pressure drop (5 psi max.) at the required cfm air flow.
Installing an air pressure regulator allows the option of blasting at low pressure. When blasting
at low pressure the air supply to the deadman blast control system must be at least 80psig (see
Figure 5.3 and 5.4). The valves in the abrasive blast system are “spring closed” and therefore
require at least 80psig to operate properly. If the air pressure regulator is set below 80psig the
air supply to the blast controls must be taken upstream of the regulator.