Envirco BSC - Manual (Page 20)

20
V
、SERVICE AND COMPONENTS
5.1 Main components replacement
All the components need replacement (except for the control panel, see 5.1.4, installed on the
top of the work area). Access to this area is via the removable front panel. Unqualified persons
are not permitted to perform the maintenance. It is a necessity that the safety cabinet be
sterilized after the front panel has been opened.
5.1.1 Replacement of the HEPA filter
The HEPA filter requires replacement when the motor/blower assembly cannot overcome the
rise in static pressure, causing dirt to collect on the upstream filter face and reducing the ability
to maintain the air velocity through the HEPA filter. The life of the HEPA filter depends on the
cleanliness of the surroundings and the overall operation time. The pressure monitor can
inspect the HEPA filter, and a record should be kept as time proceeds. When the average
hand intake velocity and average downflow air velocity are outside of the lowest ranges
indicated in APPENDIX I and there is no adjustment left on the fan speed control, the HEPA
filter will require changing. It is essential that the correct size replacement HEPA filter be used.
The filter size and its efficiency are marked on the label attached to the side of the existing
HEPA filter.
The correct size and type are as follows:
Model Exhaust Filter Supply Filter
11228 BBC 86 700X480CX69 1223X570X69
Type: HEPA filter, filter efficiency≥99.996%, the frame materials are metal.
NOTE: All HEPA filters can be ordered from Envirco. After replacing the filter, one
must test the filter and the air velocity. Calculate the air flow by the filter dimension
and air velocity to make sure it can meet the blower and exhaust air velocity requested
in APPENDIX 1.
5.1.2 Removal of the filter
(a) Sterilize the safety cabinet: If the equipment has used toxic chemicals, consult your Safety
Office for guidance.
(b) Disconnect from electrical source
(c) Open the operational panel using the supports. See Figure 8.
(d) Remove the side panel, either side.
(e) Remove the hex screws used to secure the glass guide and remove the guide.