Functional Description; Closed-Circuit Breathing Apparatus; Electronic Monitoring System - Dräger PSS BG 4 RP Instructions For Use Manual

en Description
2.2

Functional description

2.2.1

Closed-circuit breathing apparatus

The PSS BG 4 RP closed-circuit breathing apparatus is a
regeneration unit with pure oxygen supply in excess pressure
version. A positive pressure in the breathing circuit prevents
ambient air from entering the system.
The breathing air is circulated in a closed breathing circuit.
The carbon dioxide contained in the exhaled air is absorbed in
a CO absorber. A disposable cartridge or a refillable cartridge
2
can be used.
The breathing air is enriched with oxygen from the compressed
oxygen cylinder:
via constant metering valve in the case of low breathing

rates
in the case of higher breathing rates additionally via the

minimum valve or a manually operated bypass valve.
Before the regenerated air is inhaled again, it flows through the
air cooler. To reduce the temperature of the inhaled air further,
and thus minimise the physical discomfort of the wearer, the air
cooler can be filled with an ice pack or a cooling cartridge.
The closed-circuit breathing apparatus is connected to a
breathing connection by means of a connecting piece. One
version of the connecting piece has a condensate trap where
the condensate from the breathing air collects during use.
A water absorber is available as an option. It is connected to
the drain valve on the breathing bag and absorbs the water
that is delivered via the valve.
To be able to use the closed-circuit breathing apparatus in
particularly low or high temperatures, the following
accessories are available:
Radiant heat protection for the breathing hose and the pro-

tective cover:
Protects against radiant heat and prevents foreign bodies
penetrating through the openings into the carrying frame of
the closed-circuit breathing apparatus.
Cold protection insulation:

Permits use at ambient temperatures of -15 °C to
max. -40 °C. The closed-circuit breathing apparatus must
be stored at a minimum temperature of +10 °C.
2.2.2

Electronic monitoring system

The electronic monitoring system comprises a sensor unit,
switch box and Bodyguard. The electronic monitoring system
is connected to the breathing circuit via the control line.
The sensor unit measures the available oxygen pressure in the
compressed oxygen cylinder and the pressure in the breathing
circuit. The values are compared in the switch box. Alarms are
triggered at specific values.
The following information is displayed on the Bodyguard in
normal mode (operating mode display):
42
1
bar
1 Oxygen pressure, analogue
2 Oxygen pressure, digital
3 Remaining period of use up to the beginning of the first
remaining pressure warning in minutes
The Bodyguard issues the following warnings:
first remaining pressure warning

The warning sounds at 50 to 60 bar with the relevant coun-
try-specific settings. When this warning sounds, approx.
75 % of the oxygen has been used up. The Bodyguard is-
sues an intermittent tone for 30 seconds and the red LEDs
flash continuously.
Second remaining pressure warning

When this warning sounds, approx. 95 % of the oxygen
has been used up. The Bodyguard issues an intermittent
tone continuously and the red LEDs flash continuously.
Low pressure warning

When the device is put into operation and the cylinder is
closed, the Bodyguard issues an intermittent tone and the
"Open cylinder valve" symbol appears on the display.
The Bodyguard can function as automatic distress signal unit
and issue an alarm when the wearer is no longer moving:
When the wearer starts operation and the function key is
removed from the Bodyguard, the motion sensor is activated.
The "Motion sensor activated" symbol is displayed briefly
(see chapter 2.6 on page 44). If no further motion is detected,
a pre-alarm sounds after approx. 25 seconds. If any movement
is detected within the following approx. 10 seconds, the pre-
alarm is cancelled. If no motion is detected, the main alarm
sounds. The main alarm can be acknowledged as follows:
The function key is re-inserted.

Both buttons on the Bodyguard are pressed.

The apparatus wearer can trigger an emergency signal using
the yellow panic button if the wearer cannot retreat from the
hazard area.
The left button can be used to switch on the backlight for
5 seconds.
The ambient temperature can be displayed using the right
button.
The Bodyguard has an infrared PC interface. Optional
Windows software is available for this purpose. With this
software, the infrared interface can be used for the following
functions:
Custom configuration of the Bodyguard

2
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