MTS Model 293-22 Hydraulic Service Manifold - Manual (Page 21)

As it passes through the orifice into the control circuit, the initial pressure is decreased substantially. As
the control circuit fills, the slow turn-on accumulator begins to fill, extending the pressure rise time and
slowing the rate at which the main control valve operates. Control circuit bleed-off through the low-pressure
control also increases the time required for the main control valve to balance. A controlled, gradual increase
(or decrease) occurs during the shift from low to high pressure (or from high to low pressure).
HSM Rapid Pressure Reduction
The control manifold dumps hydraulic pressure rapidly when the high and low solenoid valves are
de-energized simultaneously to turn off the fluid flow and port the output pressure line to the return line.
The control circuit is connected to the drain line and pressure in the control circuit drops rapidly, allowing
downstream pressure and a control spring to close the main control valve. HPU pressure is disconnected
from the pressure output. At the same time, the pressure output is connected to the return line by the main
control valve, and the pressure accumulator is drained.
Model 293.22 HSM Hydraulic Schematics
The following figures show the hydraulic schematics for the single-channel and multichannel versions of
the HSM.
Single-Channel Hydraulic Schematic
Model 293.22 Hydraulic Service Manifold | 21
Introduction