Model 30000-S DHPU Manual
Rev. 0
JRK
17SEP12
Page 12
Verify the interconnect hoses or piping is adequate for the maximum flow generated
from the power unit. Undersized lines will lead to a buildup of heat and a decrease in
system performance. A hose set can be purchased separately with connectors
matching the power unit installed.
For quick installation and to reduce spills on connection, the power unit is equipped
with quick disconnects. Never connect or disconnect the lines when the power unit is
running. Before connecting the quick disconnects to the unit, ensure that the faces of
the connectors are free from debris. Remove any particles with a lint free rag. Dust
plugs and caps are included with the connectors to prevent contamination during
transportation and storage. Connect the pressure and return lines using the quick
disconnects. The connectors are threaded with a wing style construction. Full thread
engagement must be met before the integral check valve in the connector is forced to
open. The following photo shows the location of the pressure and return quick
disconnects.
Figure 5: Quick Disconnects and Ball Valves Location
Operation
The DHPU is a simple unit that provides pressure and flow for an open center hydraulic circuit such
as a tong. This unit is not intended to work in conjunction with closed center valves. Closed center
valves have the pressure port blocked in the neutral position. Heat builds up in the system quickly
as the full flow of the system is dumped over the system relief since the flow cannot return to tank
through the valve.
The prime mover for the hydraulic pump is the diesel engine. The engine rotates the pump shaft at
the speed selected and the torque output is dictated by the load on the pump. This model has two
fixed displacement gear pumps coupled to the engine. The first gear pump has two sections and
provides hydraulic power to the open centered circuit. The other single section pump's purpose is
to supply power to the heat exchanger's motor. It is mounted on the engine's auxiliary pad.
