Heyer Modular+, Service Manual

Page: 28 / 114

Repair Information
28
2.14.5 Pneumatic driving module
The driving module consists of the proportional valve and flow divider with an internal flow sensor. The
proportional valve supplied by the HP pressure reducer generates a driving gas flow of 0-75 l/min in
relation to the control voltage of the proportional valve of 0 - 5VDC.
The control voltage of the PV, required for the pre-selected parameter settings, is generated by the
CPU board AVM 3-2.
The driving gas flow Qdrive gas is in the following in relationship with the tidal volume:
Qdrive gas = VT/Ti with
Qdrive gas = driving gas flow
VT = generated tidal volume
Ti = Inspiratory time
2.14.6 Flow metering module
The flow metering module attached to the proportional valve consists of a flow sensor with a
measuring range of 0 - 1 l/min and a flow divider. The flow divider splits the total flow in a ratio of 79: 1,
and the bypass flow is lead to the flow sensor. A closed loop that allows high accuracy and back up in
the generation of the tidal volume results from this configuration via the module 2 CPU-boards.
2.14.7 Tube color coding
Despite the local color coding system, all the pneumatic tubes inside the apparatus will be according
to the coding label inside the unit, if it is not according to the local color coding system, next to the flow
meter block. Typically it will be according to one of the follow standards.
Gas
ISO 32 Standard US standard
O
2
White Green
N
2
O Blue Blue
AIR Black/White Yellow
On the outside of the apparatus, the coding will be as ordered.