Page 208 - Florida Pest Control Examinations

COMPRESSED-AIR SPRAYER EQUIPMENT

(Courtesy of UNIVAR)

A compressed-air sprayer is just what you would expect-- when you pump it, air goes into
the pump cylinder and into a reservoir tank. It only takes 15-20 pumps to pressurize the
tank to about 20 psi, which is the proper pressure for most applications. If you have to
pump much more than that, or have to re-pump every few minutes to keep up the pressure,
your spray tank is not working properly. There are several parts to check that could fix the
problem.

PLUNGER CUP

If you push on the handle and feel no resistance, or you hear no air going into the tank,
there may be a problem with the plunger cup. Some sprayers have plunger cups made of
leather. They can be treated with NEET’S-FOOT OIL. Thoroughly rub it into the leather. If
that does not take care of the problem, go ahead and replace the plunger cup.

For sprayers with plastic plunger cups, the only thing you can do is replace it. If the tank is
slightly dented, replacing with a leather plunger cup may seal the problems. If the dents are
too severe, there is not much you can do to make the seal work again.

PUMP CHECK VALVE

The pump check valve is used to prevent water from going back into the cylinder while al-
lowing air to be pushed out of the pump. If the inside of the pump cylinder is wet, it could be
that the rubber valve is clogged and/or not sealing. If it is clogged, it is a simple matter of
just cleaning it. Sometimes they are quite worn or cracked, and will have to be replaced.

TANK GASKET SEALING RING

The pump cylinder fits to the top of the tank with a gasket. This gasket is a ring that seals
the tank. If air is being forced into the tank, but there is still no pressure, check the tank
gasket sealing ring for cracks. They are also easy to replace when worn out.

208