DirectFlo DF1400
Chapter 3: Using the DirectFlo
Comco Inc.
3-6
Issue Date: January 2009
Tank Orifice
The powder basket within the abrasive tank is fitted with a single orifice at the bottom
through which all powder must pass (see Figure 3-1). The amount of powder flowing is
directly proportional to the size of this opening.
As seen in the table below, a small increase in the diameter of the tank orifice results in
a large increase in the area of the opening. In other words, increasing the tank orifice by
only a few thousandths of an inch, can almost double the amount of powder that will
pass through it and out the nozzle. This is a very important factor, since the number of
abrasive particles striking the work surface has a direct relation to the speed of the
cutting action.
Diameter, in.
Area, in
2
.
Comco P/N
0.018
2.5 X 10
-4
MB1409-18
0.025
4.9 X 10
-4
MB1409-25
0.030
7.1 X 10
-4
MB1409-30
0.040
12.6 X 10
-4
MB1409-40
0.060
28.3 X 10
-4
MB1409-60
Some judgment is required in selecting an orifice. A very small orifice should not be
used with powders of large particle size. Likewise, a very large orifice may cause a
small nozzle to plug from excessive powder in the line. See Table 3-3 for guidelines in
selecting orifice size.
The DF1400, as shipped from the factory, is equipped with the 0.025" diameter orifice
(MB1409-
25). A .030” orifice is provided in the accessory parts kit. The orifice will have
a number stamped on the side that corresponds to the dash number, and opening size.
Refer to the table above to determine the size.
To change the tank orifice, refer to the procedures in Chapter 2, “Set-up and Test”, to
remove the powder basket from the tank. The tank orifice can then be removed from the
powder basket with a 1/4" nut driver (see Figure 3-1). The replacement orifice should be
installed securely, but not too tight. Insert the powder basket back in the tank and
replace the tank cover.
For improved performance and longer life, all Comco orifices are carbide lined.
Rev
5/2014
