| VARIABLE
CONTROL HEAD MODEL 20DV, 20CPV
The
Variable Volume Control head mounted on a standard
Tri-Rotor pump body allows for both automatic
and/or manual changes in the flow rate of the
pump. The automatic response occurs with changes
in the operating pressure of the system, causing
a spring-loaded hydraulic control mechanism to
adjust internally, the stroke of the pump. By
using flow controls, the operator can make manual
adjustments to increase or decrease the discharge
rate as desired.
MANUAL
AND VERNIER FLOW CONTROLS
Two
flow controls are available: the Manual Flow Control
(MFC) for rough adjustments, or Vernier Flow Control
(VFC) which is graduated for fine setting and
metering. These enable the operator to vary the
discharge rate infinitely from 100% down to zero
without stopping the pump or changing speed. The
plunger under the control stem and control lever
assembly, fix the stroke length, i.e. displacement
of the pistons.
TO
ADJUST CONTROL SPRING TENSION (3 STEPS)
 STEP
1 - STOP PUMP. Unscrew lettered spring cap
and insert spring adjusting wrench as shown. Pull
wrench toward "increase" and remove
pawl pin. DO NOT LET WRENCH GET AWAY. NOTE alignment
of holes between pawl plate and underlying top
spring plate. Unwind to release spring tension,
counting number of top spring plate holes passing
hole originally containing pawl pin.
STEP
2 - To reset, pull wrench in direction of
"increase" (note arrows on head shell)
until the spring begins to tighten against the
control lever assembly. Note first coinciding
set of holes. Thereafter, continue turning wrench,
DO NOT LET WRENCH GET AWAY, until third top spring
plate hole is seen. Insert pawl pin to lock top
spring plate in this position. Pump will now develop
approximately 25 PSI when running against a closed
discharge line.
STEP
3 - For greater pressure, turn wrench to higher
hole position. With standard spring, each hole
represents 5 PSI, DO NOT EXCEED 7 holes. Heavy
duty spring gives approximately 12 PSI per hole,
DO NOT EXCEED 7 holes, at which, its maximum setting
of 100 PSI has been reached.
CAUTION:
Spring adjusting wrench is designed to bend if
operator exceeds the allowable tension.
TO REVERSE DIRECTION OF ROTATION.
The
rotation of the 20DV, 20CPV pump may not
be reversed in the field for extended periods
of time. The pump may be run in reverse TEMPORARILY
for such purposes as stripping the lines, etc.
- To
reverse direction of rotation, a variable control
head pump of opposite rotation must be ordered
from the factory. See "putting pump into
service" section on page 1.
|
Contact/RFQ 
