1-1
Valco Cincinnati, Inc.
SECTION 1 - INTRODUCTION
SECTION 1 - INTRODUCTION
SECTION 1 - INTRODUCTION
SECTION 1 - INTRODUCTION
SECTION 1 - INTRODUCTION
This DD-1 air-driven, electronically controlled, double-diaphragm pump is a
process pump composed of two interchangeable diaphragm assemblies
driven by shop air to deliver fluid.
The DD-1 is designed to deliver fluid on a continuous or intermittent basis.
The two interchangeable diaphragm assemblies are mounted within a
frame. The shafts of each diaphragm assembly are coupled so as one
diaphragm is being driven to deliver fluid under pressure, the other
diaphragm assembly is being recharged with fluid.
Cycling is achieved electronically, instead of mechanically. Two reed
switches are mounted in a control box and are activated by a magnet
attached to the shaft coupler (chain link). The switch signal passes to an
electronic control circuit mounted in the control box that in turn operates
standard 3-way solenoid air valves. Flow is controlled by check valves that
are mounted in the corner sections.
The DD-1 pump starts dependably, runs more smoothly, and operates at
lower pressures and temperatures than ordinary mechanically controlled
diaphragm pumps due to its electronic control system. The DD-1 does not
use a spool valve that can stick or shorten the stroke of the pump. The
switches are either open or closed. Therefore, the pump starts from any
position at an inlet air pressure sufficient to overcome internal friction and
system head pressure. Lower temperature operation is also achieved since
there is no rapid expansion of drive air inside the pump. The 3-way valves
exhaust directly to the atmosphere. Reversal cannot occur until a switch is
tripped. Electronic reversal is also fast. The speed of reversal and the
consistency of volume on each stroke contributes to produce a very smooth
flow of fluid.
The DD-1 pump can be ordered with one or two inlet ports and two
discharge ports. Each diaphragm chamber is a single-acting pump. Because
of its electronic reversing control, the DD-1 has the unique advantage over
any other dual, single-acting diaphragm pump. The stroke can be offset
electronically so that the output from one side is as much as 50% greater
than the other. For closed-loop, recirculating systems like those used in
flexographic printing, the pump can be set up so that the amount of fluid that
one side of the pump supplies to the reservoir is less than what the other
side is capable of pumping away. This assures that the reservoir never
becomes over-filled.
Service is easy since the diaphragm assemblies are interchangeable and
individually accessible. Each check valve is externally accessible and the
air valves are standard devices that are coupled directly to the diaphragm
housing through quick-disconnect fittings. Most service requirements can be
accomplished without removing the pump from the system.
Five indicator lights are provided on the pump PC board to facilitate
electrical service.
