Service and components 20 – Envirco BSC User Manual

Page 20

、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

(d) Remove the side panel, either side.

(e) Remove the hex screws used to secure the glass guide and remove the guide.