Datascope System 98 Service Manual page 162

Figure 2-2
e Drive System
The System 98 pneumatic drive system consists of four solenoid valves (KO, K6A,
K7,KS8), the pump, an air filter, pressure and vacuum reservoirs, a pressure
regulator, and a pressure relief valve.
The function of the drive system is to cycle pressure and vacuum to the Safety
Disk which causes it's internal diaphragm to toggle from side to side. [AB
inflation occurs when the diaphragm is pushed against the IAB (patient) side of
the Safety Disk. [AB deflation occurs when the diaphragm is pulled against the
drive side of the Safety Disk. "
The pressure output from the pump is regulated to about 8 PSIG via a back
pressure regulator (RG2). The back pressure regulator allows excess pressure to be
vented to atmosphere. The vacuum output from the pump is not regulated since
there 1s no hazard in having too high a vacuum level.
Sotenoa |N、 ノ
Pressure Kg
Solenord
Safety Disk
9 P.SI
Reta! Valve
RG2
: E
! πας Mutter
VACUUM | PRESSURE s
Shown in the activated state. The vacuum solenoid (K7) RÉSERVOIR | RESEAVOR | 8 PS!
Back Pressure
i
To Solenog
Dnver PCB
is open applying vacuum to the drive side of the Safety Bağlar
Disk causing the intemal diaphragm to be pulled back.
This results in a deflated balloon. I 1 é
Variable augmentation is achieved by partially inflating the patient balloon. Via
the front control, the user proportionally abbreviates the time during which the
drive pressure valve, K8 is open. This reduces the effective pressure applied to the
disk membrane. If the pressure is sufficiently low, the membrane does not fully
"toggle" (conform to the disk walls). Hence only a portion of the disk's tidal
volume is expelled, thus yielding a partial inflation of the patient balloon.
Large pulsations, inherent in diaphragm pumps, are filtered via reservoirs (RES1).
The reservoirs also supply instantaneous demands for both pressure and vacuum
which are present during inflation (pressure) and deflation (vacuum) of the IAB.
The default state (all solenoids de-activated) of the drive system has the safety
disk vented to atmosphere via KGA, a normally open valve. Back pressure on the
LAB, ie. blood pressure, causes the balloon to remain deflated.
2-50
System 98 Service Manual
Chapter 2, Theory of Operation