Schmidt MV3, Руководство по эксплуатации и обслуживанию

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Copyright © 2021 Axxiom Manufacturing, Inc.
11.3 Notes on Abrasive Flow Problems
11.3.1. Contaminated Abrasive
Air quality is crucial to the operation of an abrasive blaster. Moisture and
contaminants can cause components to malfunction. Moisture condensation in a
blast system causes abrasive flow problems. Condensation occurs when the hot
vapor-filled compressed air cools as it reaches the abrasive blaster. Water droplets
formed during condensation can be absorbed by the abrasive in the blast vessel
which can cause erratic flow to the abrasive valve. To minimize the chance of
abrasive flow problems a moisture removal device installed for the blast system air
supply is highly recommended (i.e. coalescing moisture separator, air-cooled
aftercooler or deliquescent dryer). Contact a local authorized Schmidt® distributor
or Axxiom Manufacturing, Inc. to locate one near you.
Do Not hammer on any part of the pressure vessel to improve abrasive flow. This
can cause cracks that may lead to pressure vessel rupture.
11.3.2. Choking the blast outlet
The choke valve (#13) is used to clear any trash that may get into the blast vessel
and block the MV3 Valve orifice. Whenever trash (paint chip, cigarette butt, etc.)
blocks the abrasive valve orifice, the procedure is to fully open the valve by turning
the knob counterclockwise, then press down the deadman lever (#12) to begin
blasting. While blasting, have an assistant close the choke valve completely for
about one second. This creates differential pressure at the abrasive valve (high
pressure above; low pressure below). The higher pressure from the blast vessel
should be enough to loosen the trash blocking the abrasive valve orifice and blast it
through the blast nozzle (#11). To minimize excess wear of the MV3 Valve keep the
choke valve fully open during normal blasting.
Note: Trash cleared during the choking process may block the nozzle orifice. Refer
to Item (8) in Section 11.2.4 for procedure to clear nozzle.
Note: The MV3 Valve includes a cleanout port to that can also be used in the choke
procedure. Remove the cleanout cap (#16) then choke as detailed above. Reinstall
the cap when complete. See the valve drawings in Section 9.5.
11.3.3. Blast control hoses
Remember, the blaster controls and valves are normally closed. Therefore, the
control hoses are depressurized to turn the blast off and pressurized to turn the blast
on. If a needle gauge is available, it is the quickest way to check to see if there is
pressure in the control hoses. If no needle gauge is available, disconnect each control
hose fitting one at a time until the problem is located.
11.3.4. Recycled Abrasives
Used and recycled abrasives can contain trash & coating particles removed from
previously blasted items (particularly sticky coatings) that can cause abrasive to
clump together and block the metering valve orifice and stop flow. Prior to use
recycled abrasive must be passed through a screen with openings no larger than 1/4”
round. Some applications may require smaller openings. Refer to Section 11.3.4.
Recycled abrasive can contain trash that can cause equipment malfunction. Prior to
use, recycled abrasive must be passed through a screen with openings no larger than
1/4” round. Some applications may require smaller openings.