Pellerin Milnor Corporation 11
CAUTION:
Injury and Damage Hazard — Improper wiring can cause the machine
to malfunction, risking injury to personnel, damage to machine compo-
nents, and damage to goods.
� Electrical and piping connections described in this section must be
made only by qualified, authorized personnel.
� Lock off and tag out power at the external disconnect switches for the
washer-extractor before proceeding.
� Do not rely merely on the information in this section when wiring. Consult all applica-
ble electrical schematics.
� Do not reroute or rearrange any wires not specifically permitted by this instruction.
� Do not connect a common wire to ground. Use the common terminal furnished.
CAUTION: Risk of Poor or Inconsistent Wash Quality — Injection times of less
than 10 seconds are discouraged because fine adjustments are not possible,
and factors such as pump lag time may cause significant variations in the amount of
chemical delivered.
� Size pumps or valves small enough for adequate control (i.e., for longer injection
times).
� Use two pumps or valves to inject a small or large quantity of the same chemical, if
required.
1.5.1 Maximizing Chemical Injection Precision
BNCOUI01.C02 0000188933 A.5 A.6 1/2/20 1:25 PM Released
Injection of a consistent amount of chemical is important in controlling wash quality and using
chemicals economically. When chemicals are injected by units of time, as is done with most
washer-extractors, injections of short duration can be imprecise because of two reasons:
• Fine adjustments to the delivered quantity are not possible. For example, if an injection of
three seconds is extended by one second, the quantity delivered is theoretically increased by
more than 30 percent. However, if an injection of 20 seconds is increased by one second, the
theoretical quantity is increased by only five percent.
• Variations in the time between the start of the chemical signal and the start of the chemical de-
livery into the machine can cause significant differences in the quantity of chemical injected.
In this case, if a pump starts more slowly some times than others, or if the delivery tubes are
partially empty at the start of the inject period, the quantity of chemical delivered may vary
significantly. As an example, assume a peristaltic pump moves chemical along the delivery
tube at a rate of three feet per second. If the delivery tube is empty for three feet along its
length, then one second of the injection time is spent injecting air rather than chemical. If the
programmed injection time is only three seconds, then one third of the desired chemical is not
being delivered. However, if the programmed injection time is 20 seconds, the chemical de-
livery is only five percent less than desired.
• Increasing the programmed injection time makes any variation less significant. Use pumps
and/or valves sized to allow inject times of at least 10 seconds. If injection times for a specific
chemical vary widely from one formula to another, consider using two pumps or valves for
Commissioning
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