Water Inlet Pressure Switch Water Pressure Gauge Residue/Lime Water Agitator Motor Control Center Automatic Lubrication Panel Water Level Valves Residue/Lime Water Drain Valve & Control Flashback Arresters Safety Valves Plant Alarms

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Acetylene Generators – Part II

2. Water Inlet Pressure Switch
Description: This switch constantly monitors the inlet water pressure to the generator. If it falls below a preset
level then the complete generator acetylene production is shutdown. The setting is password protected and
can only be changed by management.

3. Water Pressure Gauge
Description: Indicates the water pressure when water enters the generator tank. A minimum of 35 PSI (241.5
kPa) water pressure is needed at the generator. Gauges come in PSI or kPa readings.

4. INTERNATIONAL, INC.
Residue/Lime Water Agitator
Description: The electrically driven agitator is used to intermittently stir the lime water residue. It
consists of a shaft which runs the length of the generator tank to which are attached a number of
paddles. These agitate the lime slurry preventing solids from settling at the bottom of the generator
tank.
Note: Settling can cause high-localized temperatures due to insufficient water mixing with the calcium
carbide.
The agitator runs every time the screw feed operates and is also on a timer that should be set to rotate
for 2 minutes in every 10. It must remain switched on even when not producing acetylene to prevent
lime settling in the tank.

5. INTERNATIONAL, INC.
Motor Control Center
Description: The MCC uses a Siemens S700 series PLC. This PLC controls all the functions of the
plant and signals malfunctions with and audible alarm bell and a color visual display. A monochrome
display is optional in the manifold room so that operator can react faster to alarms.
Siemens S700
series PLC

6. INTERNATIONAL, INC.
Automatic Lubrication Panel
Description: The lubricator panel supplies grease to the agitator shafts, 24 hours a day, seven days a
week. It reduces agitator shaft wear and slurry leaks. A timer panel that uses nitrogen operates the unit.

7. INTERNATIONAL, INC.
Water Level Valves
Description: Situated at this end of the generator tank are the 3 manual valves for checking the water
level (high, middle and low) when filling the tank and during routine operation.

8. INTERNATIONAL, INC.
Residue/Lime Water Drain Valve & Control
Description: This valve discharges lime slurry as the water level in the generator tank rises as a result
of incoming water.
When the generator tank level rises the proximity switch is activated, causing the drain valve to open.
As the level lowers the proximity switch is deactivated causing the PLC to shut off the solenoid and to
remove the air from the drain valve actuator and closing the drain valve by using a spring.

9. INTERNATIONAL, INC.
Flashback Arresters
Description: Two water filled flashback arresters are fitted to the generator tank outlet lines to prevent
an accidental flame from entering the generator tank.

10. INTERNATIONAL, INC.
Safety Valves
Description: There are five safety valves fitted to the generator. Two are in the tank riser and one on
each of the two flash back arresters. If the generator tank pressure should become excessively high
(over14 psig or 105 kPa) one or all these safety valves will open to relieve pressure. These valves can
be operated manually to vent the generator of acetylene or nitrogen/air mixtures. The fifth valve is a
high capacity located on the generator tank to ensure the pressure can be relieved quickly.

11. INTERNATIONAL, INC.
Plant Alarms
Description: All alarms are displayed on a touch screen panel. These alarms can be acknowledged
which will silence the audible alarm for a set amount of time if the alarm situation in not corrected. The
alarm is displayed with the time and date of the alarm. After the alarm has been corrected it can be
removed from the screen by the reset button.

12. P. O. Box 7, West Alexandria, Ohio 45381 USA
Telephone 937-839-4604
Fax 936-839-5897
www.rexarc.com • info@rexarc.com