Blast Tips
Sheet 4622/4624
Mixers. Tips can be fed with premix from either 3070 Inspirator mixers or 3065 Aspirator Mixers. Manifold pipe size generally should be the same as the mixer outlet. On end-fed manifolds, allow five pipe diameters between the mixer and first blast tip. The advantage of inspirator mixers is they require few components and very little piping. Because they use high pressure natural gas to entrain air into the manifold, inspirator mixers don’t need a blower. See bulletin 3070 for more information.
4624 Stainless Steel Blast Tips are small, self-piloted premix burners, that are manually lit with a torch or other external iginiton source. Mounted on pipe manifolds, they are well suited for such applications as corebox and mold spot heating. They burn natural or LP gases premixed with air. The old 4622 cast iron version is now obsolete, replaced with the 4624 which has the same capacity and connection size.
Operation . For longest tip life, operate blast tips at or near stoichiometric ratio about 4"w.c. (10 mbar) mixture pressure. For added capacity, they can be run slightly rich in the presence of secondary air. — Maximum mixture pressure for stability is slightly over 10"w.c. (25 mbar) — Minimum mixture pressure to avoid flashbacks, is 0.25"w.c. (.62 mbar) — Maximum ambient temperature is 800 °F (427 °C). Installation . Tips should be threaded into half couplings welded to pipe manifolds, spaced closely enough for uniform heating. Minimum tip-to-work spacing, for uniform non-impingement heating, is 4" (102 mm) on stoichiometric ratio at 4"w.c. (10 mbar) mixture pressure. Shorter tip-to-work spacing can be used if impingement heating is desired.
Typical center fed manifold with 3070 Inspirator mixer providing premix.
The advantage of aspirator mixers is they can provide higher mixture pressures, work with a wider range of fuels and offer more control flexibility. High pressure gas is not needed as blower air pulls the gas into the mixer. See bulletin 3065 for more information.
Minimum 5 header diameters between mixer and first tip
weld half couplings over holes in manifold
blast tip
Typical end fed manifold with a 3065 aspirator mixer to provide premix
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