Tec 5 Vaporizer
Page 19
O & M Manual Part No. 1105-0100-000
August 1999
6.4
Gas Flow Through The Vaporizer
6.4.1
General
The output concentration of the Tec 5 vaporizer is regulated by the 'variable flow-split' method
described in the following text and illustrated on Fig. 16 and 17:
A total flow of fresh gas from upstream flowmeters enters the vaporizer at
1
where it is immediately
split into two streams. One stream flows into the fresh gas by-pass circuit and the other stream flows
through the vaporizing chamber where it is enriched with the vapour of the liquid anaesthetic agent.
6.4.2
By-pass Circuit
The by-pass circuit includes the gas transfer manifold and also a thermostat assembly which is located
at the base of the vaporizer.
The fresh gas flows through the by-pass circuit vertically downwards from
a across the sump base
b
, through the thermostat to
c and back up the gas transfer manifold via
d to e as illustrated on
Fig. 16.
The thermostat deflects according to its temperature to control the resistance offered to the flow of gas
through it. This deflection varies the relative proportions of gas flowing through the by-pass and
vaporizing chamber circuits, as described in Section 6.3.
FROM
FLOWMETER
FLOW CONTROL
(VAPOUR CHANNEL)
VAPORIZING
CHAMBER
THERMOSTAT
SHUT-OFF
OPEN
ROTARY
VALVE
TO COMMON
GAS OUTLET
Fig. 16 Vaporizer Flow - Schematic Diagram
6.4.3
Vaporizing Chamber Circuit
The fresh gas flow through the vaporizing chamber, illustrated on Fig. 17, flows from
1
across the
sump cover
2
where it is diverted via
3
through the central cavity of the rotary valve and back
through the Intermittent Positive Pressure Ventilation (IPPV) compensating assembly via
4
,
5
and
6
.
Gas now flows from the IPPV assembly via
7
down through the tubular wick assembly where it picks
up anaesthetic vapour and then flows across the base of the vaporizing chamber above the liquid agent
to
8
.
From the base of the vaporizing chamber the gas/agent mixture flows via
9
through the sump cover to
the proportional radial drug control groove of the rotary valve and then back into the sump cover
bk
where it combines
bl
with the fresh gas from the by-pass circuit.
The combined total flow then flows out from the vaporizer and via the Selectatec circuitry to the anaesthesia
system common gas outlet.
1
a
b
c
d
e
11
10
7
4
3
014A T5 OM
AA.13.062
