5
Section II
–
Description
This manual contains operation, service and overhaul
information for Vickers hydro-cushion type pressure control
valves.
The
“
R
”
and the
“
RC
”
series valves are identical in operation
except the
“
R
”
series limits flow to one direction - from the
primary port to the secondary port. The
“
RC
”
series,
provided with an integral check valve, permits reverse free
flow from the secondary port to the primary port when the
valve is closed.
Since these valves can be internally or externally drained,
directly or remotely operated, they are adaptable to a wide
range of applications depending on the position of the covers
in relation to the body.
Figure 1. 6.
Type 1
Type 2
Type 3
Type 4
Drain
Plugged
Control
Port
Plugged
Remote
Control
Connection
Offset
from
Body
Passage
External Drain
Connection
Drain
Plugged
Align
with
Body
Passage
Align
with
Body
Passage
Align
with
Body
Passage
Offset from
Body Passage
NOTE:
Cover positions illustrating threaded style valves apply to gasket mounted valves also, except the cover ports remain
plugged. External connecitons are made directly to the mounting surface or subplate fo the RG, RCG Series.
The four standard combinations are designated as Types 1,
2, 3, and 4. Each type is available with or without the integral
check valve, permitting reverse free flow.
TYPE 1
- is internally drained and directly operated. It is
used as a relief valve for overload protection when the sys-
tem pressure does not exceed 500 PSI. In this application
the secondary port is connected directly to tank. Or, if pro-
vided with the integral check valve, it can be used as a coun-
terbalance or brake valve.
TYPE 2
- is externally drained and directly operated. It is
used as a sequence valve permitting pressure buildup for
the second phase of a two phase cycle, while maintaining a
minimum pressure at the primary port for a holding opera-
tion, i.e., a clamp and work stroke cycle.
TYPE 3
- is externally drained and remotely operated. It is
used as a sequence valve in the same manner as
Type 2
except, being remotely operated, the valve can be used to
sequence independently of the primary pressure when pro-
vided with a separate pressure source.
TYPE 4
- is internally drained and remotely operated. It is
used primarily as an unloading valve where the secondary
port must be connected directly to tank. Application of exter-
nal pressure permits the valve to open fully independent of
the primary pressure. Type 4 valves can also be used as
remotely operated counterbalance or brake valves when
provided with the integral check valve.
