Visual Check; Toco Ventilation/Belt Button; Testing The Ventilation Membrane - Philips Avalon CTS M2720A Service Manual

6 Preventive Maintenance and Safety

Visual Check

Ensure there are no cracks in the transducer housing. Make sure the battery drawer fits properly into the
transducer housing, and that the sealing lip is in good condition. Inspect the LCD window, and if there is
water or condensation behind the window, replace the transducer. On the ECG transducer, ensure that
the adapter cable socket is not damaged.

Toco Ventilation/Belt Button

The Toco transducer requires air exchange for drift-free operation (see also the section "Underwater
Monitoring" in the Instructions for Use). This is done by a ventilation membrane incorporated in the belt
button. The effectiveness of the ventilation membrane should be checked at least once a year to ensure
that free air exchange takes place. If the membrane is congested, the belt button must be exchanged (see
the instruction sheet, "Removing and Replacing the Transducer Belt Button" that accompanies the belt
button replacement kit, or see page 91 in this manual).

Testing the Ventilation Membrane

If you want to test the ventilation membrane in the belt button, you need the following:
• Manometer.
• Test volume chamber.
• Three lengths of silicone tubing with a 'T' adapter.
Remove the belt button from the transducer using the special tool (see the instruction sheet "Removing
1
and Replacing the Transducer Battery/Belt Button").
Connect the manometer to the volume chamber using two lengths of the silicone tubing and 'T'
2
adapter as shown. Connect one end of the remaining length of silicone tubing to the 'T' adapter, and
the other to the threaded end of the belt button.
3 Apply pressure with the manometer (for example, 250 to 260 mmHg).
Release the manometer valve. The pressure should fall rapidly, to indicate that the membrane is
4
functioning correctly.
56
Silicone
tubing
Belt button
Regular Preventive Maintenance
'T' adapter
Manometer