25/08/2004 ©
Söring
Service-Manual Arco- and RF-units
1
not valid for A-3000/ -2000
2
not valid for Arco-2000
-50-
3
not valid for MBC600
4
not valid for Arco-1000
11. Description of gas-system
1
11.1. External gas-system
The pressure regulator of the gas bottle (2-step pressure reducer) reduces the bottle
pressure to the equipment input pressure of 8 bar. In order to make connections of
regulator to gas bottle and from regulator to equipment easy, all connections are
equipped with a quick-lock system. It is only necessary to tighten the regulator by hand.
After opening the gas-bottle the regulator is tightly locked to the outlet valve of the gas-
bottle. Additionally the regulator is equipped with a bleed-valve to let out the rest-
pressure after closing the bottle-valve. This allows an easy removal of the regulator from
the bottle (Exchange of gas-bottle). The hose connection between regulator and
equipment is simply done by plugging the gas-hose into the quick-locks.
11.2. Internal gas system (gas control unit and gas control board)
11.2.1. General description
The gas control unit serves for regulation and monitoring of Argon gas-flow with Argon
handpieces.
11.2.2. Principle of operation
The gas, adjusted to constant pressure by the pressure regulator, flows through a
proportional valve. Then the gas passes a throttle (flow resistance) and reaches the tube
of the handpiece via a filter. A pressure transducer measures the pressure before and
after the throttle. The pressure difference is an indication for gas flow. On deviations form
desired gas flow the error is corrected by a changed control of the proportional valve. As
the pressure difference is proportional to the square of gas flow (volume flow), resulting
in very small values at small gas flows, two additional throttles can be inserted between
the pressure transducer by means of two magnetic valves. This makes three gas flow
control ranges. Check of gas flow is performed by the second pressure transducer (at
the output). If a maximum pre-selected pressure is exceeded, usually caused by an
obstruction of the handpiece-tube, this error will be recognized.
11.2.3. Design of gas control unit
Fig. 11.1 shows the general design of the gas control unit.
The gas control unit consists of the following components:
- 1 pressure regulator, keeps input pressure constant.
- 2 pressure switches, check for input pressure.
- 3 proportional valve (flow control).
- 4, 5 pressure transducers, measurement of pressure difference
- 6, 7 Magnetic valves for switching throttles (ranges for regulation)
- 8,9 Throttles (flow resistances)
- 10 fine-filter (removes contaminations)
All components are mounted onto an aluminum block and interconnected.
11.2.4. Technical data
- Gas flow: 0.1 to 8 l/min in three ranges
- Input pressure 6 to 10 bar
- Output pressure max. 3 bar
- flow monitoring by pressure sensors
- precision ± 20% from 0.1 to 8 l/min
(precision depends on software used)
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