Description
B 2-2
Part 1022914G03
E
2007 Nordson Corporation
Pump Components
The pumps consist of an air motor (1) and hydraulic section (11). The air
motor powers the pump. The air pilot valves, each consisting of an actuator
(9) and valve(10), reverse the direction of air motor travel. The air valve (2)
controls the flow of compressed air to move the piston (6), connecting
rod (5), and hydraulic plunger (16). Upper and lower packings (12 and 13)
prevent coating material from leaking past the plunger. A removable
coupling (18) connects the connecting rod to the plunger. The siphon ball
check (14) and pressure ball check (15) valves control the flow of fluid
through the hydraulic section.
Pump Operation
The PermaFlo pumps are demand-type, double acting pumps. A
demand-type pump starts when the fluid pressure in the system falls below
the pressure the pump can produce with the available air pressure. The
pump stops when the fluid pressure equals the pressure the pump can
produce with the available air pressure. A double-acting pump pressurizes
and pumps coating material on both the suction stroke and the pressure
stroke.
Dead-End and Circulating System Operation
In a dead-end system, the pump starts when air pressure is applied. It
continues to operate until the fluid pressure in the system equals the
pressure the pump can produce with the available air pressure. The pump
then stalls until the fluid pressure drops, such as when a spray gun is
triggered.
In a circulating system, the pump operates continuously at a rate set by a
circulation valve. Opening the valve causes the pump to operate faster;
closing the valve slows the pump. The normal operating rate is 5 to 10
strokes per minute.
Plunger Lubrication
The solvent cup (17) contains lubricating fluid (solvent chamber fluid). This
fluid lubricates the upper part of the plunger to prevent the upper packings
from wearing excessively. The coating material being pumped lubricates
the lower packings.
NOTE:
Coating material leaking past the upper packing gland will discolor
the solvent chamber fluid and cause its level to rise. A small amount of
leakage is normal. If the solvent cup fills quickly and overflows, you can
tighten the solvent cup to compress the packings and stop the leaking. (To
tighten the solvent cup use a
3
/
8
-in. pin punch, which can be purchased
from an industrial supply company.) If the leaking continues the packings
need to be replaced. Both upper and lower packings should be replaced at
the same time.
