2920 1443 01
32
Instruction book
14. Once the water column has stabilized, adjust the pressure
differential as follows:
Remove the protecting cap from the adjusting screw, loosen
its check nut and turn the screw in to increase or out to
decrease the pressure differential. Tighten the check nut and
reinstall the protection cap.
The water level in the leg marked (-) must be:
- For MD400/800/1300/2500 W VSD and MD dryers
connected to a Z VSD compressor, at minimum flow
(compressor running loaded at minimum speed) between
5 and 10 mm above that in the leg marked (+). Also
check the water level at maximum flow (compressor
running at maximum speed). The water level in the leg
marked (-) will be approximately 30 mm above that in
the leg marked (+).
- For MD dryers connected to Z compressors with
fixed motor speed, between 20 and 40 mm above that
in the leg marked (+).
15. On water-cooled dryers, regulate the cooling water flow
through the regeneration air cooler by means of the outlet
cock (15-Fig. 1.4) until the temperature rise between cooling
water inlet and cooling water outlet is approx. 5°C.
16. Check the dryer connections for air leaks.
17.Check that the moisture indicator shows blue after
approximately 30 minutes of operation. If the moisture
indicator still shows pink after 2 hours of operation, the
pressure dewpoint is too high; consult section 5.
18. Close the blow-off valve of the air net, unload and stop the
compressor. Close the air outlet valve of the dryer.
19. Switch off the voltage.
20. On water-cooled dryers, close the cooling water inlet cock
(16-Fig. 1.4) of the regeneration air cooler.
21. Open drain valve (8).
3.2 Routine starting
1. Close drain valve (8-Fig. 1.2).
2. Carry out the steps mentioned in section "Before starting"
of the relevant compressor instruction book.
3. On water-cooled dryers, open the cooling water inlet cock
(16-Fig. 1.4) of the regeneration air cooler.
4. Switch on the voltage. On compressors with relay-
controlled regulator, check that the "MD-ON" lamp on
the control and indicator panel of the compressor is alight
(lamp test).
5. Start the compressor. The dryer motor does not yet operate
at this stage, as the compressor still runs unloaded.
6. Open the air outlet valve of the dryer and close by-pass
valve (6-Fig. 1.4). The rotor of the dryer starts rotating as
soon as the compressor loads. Note that the rotor stops
when the compressor runs unloaded.
Note: The dewpoint of the air leaving the dryer will be higher
than normal after starting. The normal operating condition will
be reached after approx. 15 minutes. If the air net is to remain
dry, a blow-off valve should be installed between the dryer and
the air net to blow off the air until the moisture indicator shows
blue.
7. On water-cooled dryers, regulate the cooling water flow
through the regeneration air cooler while the compressor is
running loaded, until the temperature rise between cooling
water inlet and cooling water outlet is approx. 5°C. Regulate
by means of cooling water outlet cock (15-Fig. 1.4).
3.3 During operation
Consult section 4, under "Daily".
Attention: Avoid short compressor loading periods and
operation at very low working pressures as otherwise the
performance of the dryer will diminish. Avoid operation at too
low a regeneration air inlet temperature (minimum 130°C).
3.4 Stopping
1. Close the air outlet valve of the dryer.
2. Unload and stop the compressor. Switch off the voltage.
3. On water-cooled dryers, close the cooling water inlet cock
(16-Fig. 1.4) of the regeneration air cooler.
4. Open the drain valve (8- Fig. 1.2).
If freezing temperatures are expected, drain the water from
the regeneration air cooler. Drain plugs are provided.
3.5 By-pass operation (Fig 1.2)
1. Close the air outlet valve (10) of the dryer.
2. Unload and stop the compressor. Switch off the voltage.
3. Open the door of the compressor regulator cabinet and move
the circuit breaker (F41 or Q2-Figs. 1.9 up to 1.15) to
position "0".
On air-cooled dryers, also switch off circuit breaker (Q41-
Figs. 1.9 and 1.10) of the fan motor. Close the door of the
cabinet.
4. Open by-pass valve (9).
5. Close air inlet valve (11).
6. Close regeneration air shut-off valve (7-Fig. 1.4).
7. Depressurize the dryer
8. Switch on the voltage and start the compressor.
When the dryer is put into service again, switch off the voltage,
re-engage the circuit breaker(s) and close the drain valve. Open
air inlet valve (11), open air outlet valve (10), open regeneration
air shut-off valve (7-Fig. 1.4) and close by-pass valve (9). Start
the compressor.
To Next Page
Loading...
Need help?
General
